When searching for the best mechanical movement books, clarity and depth are key. The Five Hundred and Seven Mechanical Movements 1908 stands out for its historic detail and precise diagrams, making it ideal for advanced students and professionals. For those new to the subject, Making Things Move: DIY Mechanisms offers accessible projects and practical insights. The main challenge in this category is balancing technical accuracy with readability—more detailed books can be overwhelming, while simpler guides might lack depth. Continue reading for a full breakdown of each top pick and what makes them unique.
Key Takeaways
- The top-ranked books balance comprehensive coverage with clear illustrations, making complex mechanisms understandable.
- Historical classics like ‘Five Hundred and Seven Mechanical Movements’ remain invaluable for detailed mechanism analysis.
- Modern guides often emphasize DIY projects and practical applications, appealing to hobbyists and educators.
- Price and depth vary widely; more technical books tend to cost more but offer greater detail, while beginner books prioritize simplicity.
- The best picks were distinguished by their clarity, relevance, and ability to serve different levels of mechanical knowledge.
| Five Hundred and Seven Mechanical Movements 1908 |  | Best for Historical Enthusiasts and Researchers | Publication Year: 1908 | Format: Hardcover | Content Focus: Historical mechanical movements | VIEW LATEST PRICE | See Our Full Breakdown |
| 507 Mechanical Movements: Mechanisms and Devices |  | Best for Engineering Students and Professionals | Coverage: Mechanical mechanisms and devices | Illustrations: Clear diagrams | Intended Audience: Engineers and students | VIEW LATEST PRICE | See Our Full Breakdown |
| 507 Mechanical Movements: Mechanisms and Devices |  | Best for In-Depth Technical Study | Content Depth: Highly detailed mechanisms | Visuals: Limited or none | Target Audience: Advanced students and engineers | VIEW LATEST PRICE | See Our Full Breakdown |
| 1800 Mechanical Movements, Devices and Appliances (Dover Science Books) |  | Best for Enthusiasts and Students Alike | Coverage: Historical and modern mechanical systems | Illustrations: Extensive and detailed | Target Audience: Students and hobbyists | VIEW LATEST PRICE | See Our Full Breakdown |
| Making Things Move: DIY Mechanisms for Inventors, Hobbyists, and Artists |  | Best for Creative Makers and DIY Enthusiasts | Content Focus: DIY mechanisms and projects | Instructions: Step-by-step guidance | Target Audience: Hobbyists, inventors, artists | VIEW LATEST PRICE | See Our Full Breakdown |
| Engineer’s Sketch-Book of Mechanical Movements: Design and Construction of Machinery; Reference for Engineers |  | Best Technical Reference for Engineers and Designers | Type: Technical reference book | Illustrations: Detailed, technical drawings | Audience: Engineers, designers, students | VIEW LATEST PRICE | See Our Full Breakdown |
| Mechanisms and Mechanical Movements: A Treatise on Different Types of Mechanisms and Methods of Transmitting, Controlling, and Modifying Direction, and Duration of Time of Action |  | Best for Theoretically Driven Understanding of Motion Control | Type: Theoretical mechanical principles | Coverage: Motion transmission, control, and timing | Audience: Students and professionals in mechanical engineering | VIEW LATEST PRICE | See Our Full Breakdown |
| 507 Mechanical Movements |  | Best Comprehensive Visual Reference | Type: Illustrated reference | Content: Mechanical movements and mechanisms | Audience: Students, engineers, educators | VIEW LATEST PRICE | See Our Full Breakdown |
| Cabaret Mechanical Movement: Understanding Movement and Making Automata |  | Best for Automata Enthusiasts and Artisans | Type: Practical craft guide | Content: Automata movement principles and techniques | Audience: Hobbyists, artisans, automata enthusiasts | VIEW LATEST PRICE | See Our Full Breakdown |
| Cabaret Mechanical Movement: Understanding Movement and Making Automata |  | Best for Beginners and Artisans Exploring Automata | Type: Beginner-friendly guide | Content: Automata principles and practical techniques | Audience: Hobbyists, beginners, automata enthusiasts | VIEW LATEST PRICE | See Our Full Breakdown |
| 100+ Mechanical Movements: An Illustrated Guide to Mechanical Mechanisms |  | Best Visual Reference for Mechanical Movements | Number of Mechanisms Covered: Over 100 | Illustrations: Detailed diagrams | Intended Audience: Enthusiasts, students, designers | VIEW LATEST PRICE | See Our Full Breakdown |
| mechanical movement book | Format | Language |
|---|---|---|
| Five Hundred and Seven Mechani | Hardcover | English |
| 507 Mechanical Movements: Mech | Hardcover or paperback | English |
| 507 Mechanical Movements: Mech | Hardcover | English |
| 1800 Mechanical Movements | Paperback | English |
| Making Things Move: DIY Mechan | Paperback | English |
| Engineer’s Sketch-Book of Mech | Print only | English |
| Mechanisms and Mechanical Move | English | |
| 507 Mechanical Movements | English | |
| Cabaret Mechanical Movement: U | English | |
| Cabaret Mechanical Movement: U | English | |
| 100+ Mechanical Movements: An | Hardcover/Paperback | — |
More Details on Our Top Picks
Five Hundred and Seven Mechanical Movements 1908
This hardcover from 1908 stands out for its detailed exploration of early mechanical movements, making it a treasure for historians and vintage engineering enthusiasts. Compared to newer books like 507 Mechanical Movements: Mechanisms and Devices, it offers a historical perspective rather than modern technical details. Its durability and extensive illustrations provide a tactile, visual understanding, but it’s limited to movements understood a century ago and lacks updates on contemporary developments. If you value historical accuracy and original craftsmanship, this book delivers. However, it’s not suitable for those seeking current mechanical innovations or practical DIY projects.
Pros:- Rich historical content and detailed descriptions
- Durable hardcover with high-quality illustrations
- Excellent for understanding early mechanical engineering principles
Cons:- No updates on recent mechanical advancements
- Limited to movements known in 1908, lacking modern innovations
Best for: Historians, vintage mechanical engineers, and collectors interested in early 20th-century mechanical design
Not ideal for: Modern engineers or hobbyists seeking up-to-date technical information or DIY projects
- Publication Year:1908
- Format:Hardcover
- Content Focus:Historical mechanical movements
- Illustrations:Detailed engravings
- Target Audience:Historians and collectors
- Language:English
Our verdict“This book is perfect for those passionate about the history of mechanical movements, but less so for contemporary practical use.”
507 Mechanical Movements: Mechanisms and Devices
This comprehensive reference excels in covering a wide array of mechanical mechanisms with clear diagrams and explanations, making it a solid choice for engineering students and professionals. Unlike Five Hundred and Seven Mechanical Movements 1908, which focuses on historical movements, this book emphasizes modern mechanisms and applications. Its broad scope and practical illustrations help readers understand how different systems work in real-world contexts, but it falls short in offering detailed specifications or insights into recent technological advances. For those needing a thorough yet accessible overview of mechanical systems, it’s highly useful. However, hobbyists looking for DIY projects or the latest innovations may find it too theoretical.
Pros:- Extensive coverage of diverse mechanical mechanisms
- Clear, well-labeled diagrams that aid understanding
- Useful as a reference for engineering applications
Cons:- Lacks detailed specifications and technical data
- Does not include recent technological developments
Best for: Engineering students, mechanical engineers, and technical professionals
Not ideal for: Hobbyists or DIY enthusiasts seeking practical projects or recent innovations
- Coverage:Mechanical mechanisms and devices
- Illustrations:Clear diagrams
- Intended Audience:Engineers and students
- Edition:Latest available
- Language:English
- Format:Hardcover or paperback
Our verdict“This book serves as a detailed reference for understanding mechanical mechanisms, ideal for students and engineers but less suited for hobbyists seeking hands-on projects.”
507 Mechanical Movements: Mechanisms and Devices
While sharing the same title as the previous entry, this particular edition offers a comprehensive overview that is especially suited for in-depth technical study. It is comparable to the 1607963345 edition but is often favored for its more detailed descriptions, despite lacking visual illustrations in the description. Compared with the 1908 book, it provides a more modern approach, but without visual aids, it may be less accessible to visual learners. This version is best for those who want a thorough understanding of mechanisms without the distraction of excessive visuals but should be avoided by beginners who rely on diagrams for comprehension.
Pros:- Detailed, technical descriptions of mechanisms
- Suitable for advanced study and reference
- Focuses on the core principles of mechanical design
Cons:- Lacks visual illustrations which can hinder understanding
- Limited coverage on recent advances or practical applications
Best for: Advanced engineering students and professionals needing detailed mechanism descriptions
Not ideal for: Beginners or hobbyists who depend heavily on visual learning tools
- Content Depth:Highly detailed mechanisms
- Visuals:Limited or none
- Target Audience:Advanced students and engineers
- Publication Year:Recent
- Language:English
- Format:Hardcover
Our verdict“This edition is ideal for advanced learners who prioritize detailed descriptions over visuals, but less suitable for visual learners or casual readers.”
1800 Mechanical Movements, Devices and Appliances (Dover Science Books)
This book offers an extensive overview of mechanical systems from historical to modern times, with detailed explanations and quality illustrations. It strikes a balance between technical depth and accessibility, making it suitable for students, enthusiasts, and hobbyists. Unlike the more specialized 507 Mechanical Movements editions, it covers a broader range of devices and appliances, providing practical insights alongside theoretical descriptions. The main drawback is its lack of digital or interactive content, and it doesn’t specify technical specs in detail. If you want a well-rounded, visually supported exploration of mechanical movements across eras, this is a strong pick.
Pros:- Broad coverage of historical and modern mechanisms
- Rich illustrations and clear explanations
- Accessible for learners at different levels
Cons:- No detailed technical specifications or modern updates
- No digital content or interactive features
Best for: Students, hobbyists, and enthusiasts interested in a broad overview of mechanical devices
Not ideal for: Professionals seeking highly technical or up-to-date engineering data
- Coverage:Historical and modern mechanical systems
- Illustrations:Extensive and detailed
- Target Audience:Students and hobbyists
- Edition:Reprint from 1800s
- Format:Paperback
- Language:English
Our verdict“This book provides a broad, illustrated overview suitable for learners and enthusiasts seeking historical and practical context, but less so for technical specialists.”
Making Things Move: DIY Mechanisms for Inventors, Hobbyists, and Artists
This book emphasizes practical, hands-on projects suitable for inventors, hobbyists, and artists interested in creating functional moving mechanisms. It stands apart from the more technical books like 507 Mechanical Movements by offering step-by-step instructions and encouraging creativity. While it lacks detailed specifications or technical depth, it compensates with inspiring ideas and accessible projects for a wide range of skill levels. The main tradeoff is its limited focus on detailed engineering principles, making it less suitable for those seeking comprehensive mechanical theory. Instead, it’s ideal for those who want to build and experiment with mechanisms in a DIY setting.
Pros:- Practical, step-by-step project guidance
- Encourages creativity and innovation
- Suitable for various skill levels
Cons:- Lacks detailed technical specifications
- No information on included materials or tools
Best for: Hobbyists, inventors, and artists looking for practical, creative projects
Not ideal for: Professional engineers or those seeking in-depth technical knowledge
- Content Focus:DIY mechanisms and projects
- Instructions:Step-by-step guidance
- Target Audience:Hobbyists, inventors, artists
- Level:Beginner to intermediate
- Format:Paperback
- Language:English
Our verdict“This book is perfect for creative minds eager to build and experiment with mechanisms, but not for those seeking comprehensive engineering details.”
Engineer’s Sketch-Book of Mechanical Movements: Design and Construction of Machinery; Reference for Engineers
This book stands out for its detailed illustrations and comprehensive coverage of mechanical movements, making it an essential reference for professional engineers and mechanical designers. Unlike 507 Mechanical Movements, which offers a broader overview, this pick provides in-depth visual explanations that are invaluable during complex machinery design. The main tradeoff is the lack of modern digital features, so it relies solely on static illustrations and explanations. It’s best suited for those who need meticulous visual references for detailed design work rather than casual reading or quick overviews.
Pros:- Extensive, detailed illustrations of mechanical movements
- Highly useful as a technical reference for design and engineering
- Clear explanations of machinery construction principles
Cons:- Lacks modern digital content or interactive features
- Primarily suited for professional use, not casual learning
Best for: Professional engineers, mechanical designers, and students needing detailed visual references for machinery design
Not ideal for: Casual readers or hobbyists seeking simple introductions to mechanical movements, due to its technical depth
- Type:Technical reference book
- Illustrations:Detailed, technical drawings
- Audience:Engineers, designers, students
- Format:Print only
- Focus:Mechanical movements and machinery design
- Language:English
Our verdict“This book is perfect for experienced engineers and designers who need precise visual references for machinery construction.”
Mechanisms and Mechanical Movements: A Treatise on Different Types of Mechanisms and Methods of Transmitting, Controlling, and Modifying Direction, and Duration of Time of Action
This book offers a deep dive into the principles behind various mechanisms, making it ideal for students and professionals who want a thorough understanding of motion control and timing. Compared with 507 Mechanical Movements, which catalogs mechanisms visually, this treatise emphasizes the theory and methods behind motion transmission and control, though it lacks practical examples. Its dense, technical explanations can be a hurdle for casual readers or hobbyists. It makes the most sense for those interested in the conceptual foundations of mechanical systems rather than hands-on crafting.
Pros:- In-depth exploration of motion transmission and control methods
- Clear focus on the principles underlying mechanisms
- Excellent resource for academic and professional study
Cons:- Lacks practical examples or step-by-step guidance
- Very technical, potentially overwhelming for beginners
Best for: Mechanical engineering students and professionals seeking a comprehensive theoretical understanding of mechanisms
Not ideal for: Hobbyists or casual readers looking for simple, practical guides or visual references
- Type:Theoretical mechanical principles
- Coverage:Motion transmission, control, and timing
- Audience:Students and professionals in mechanical engineering
- Format:Print
- Focus:Mechanism theory and principles
- Language:English
Our verdict“This treatise is best suited for those who want a detailed theoretical grasp of how mechanisms control motion and timing.”
507 Mechanical Movements
This volume remains a classic for its extensive collection of illustrations and descriptions of mechanical movements, making it a go-to resource for students and engineers alike. Compared with Engineer’s Sketch-Book, which offers detailed machinery design visuals, 507 Mechanical Movements provides a broader, more encyclopedic catalog of mechanisms. However, it does not include modern digital features or interactive content, and its technical density may be intimidating for casual readers. It’s ideal for those who need a wide-ranging visual library of movements for reference or study.
Pros:- Extensive collection of mechanical movement illustrations
- Widely recognized as a definitive visual reference
- Suitable for detailed study and design reference
Cons:- No digital or interactive content
- Can be overly technical for non-specialists
Best for: Engineering students, educators, and professionals seeking a comprehensive visual compendium of mechanisms
Not ideal for: Individuals seeking interactive or digital content, or casual learners who prefer simpler explanations
- Type:Illustrated reference
- Content:Mechanical movements and mechanisms
- Audience:Students, engineers, educators
- Format:Print
- Coverage:Wide range of mechanisms
- Language:English
Our verdict“This book is best for users who need an exhaustive visual reference for mechanical movements, especially in academic or professional contexts.”
Cabaret Mechanical Movement: Understanding Movement and Making Automata
This book excels at guiding hobbyists and artisans interested in creating automata, offering practical techniques alongside foundational principles. Compared to Cabaret Mechanical Movement (second listing), which is also beginner-friendly, this volume emphasizes understanding movement and crafting intricate figures, making it ideal for those who want hands-on skills. The lack of detailed technical specifications or comprehensive product features limits its use for advanced practitioners. It’s best suited for creative minds interested in the artistic side of mechanical movement rather than purely technical engineering.
Pros:- Practical guidance on automata construction
- Includes illustrative instructions for crafting movements
- Suitable for both beginners and experienced artisans
Cons:- Limited technical specifications or detailed engineering data
- No customer reviews available for validation
Best for: Automata hobbyists, artists, and artisan-makers exploring mechanical movement craft techniques
Not ideal for: Engineers or technical students seeking rigorous theoretical or detailed design data
- Type:Practical craft guide
- Content:Automata movement principles and techniques
- Audience:Hobbyists, artisans, automata enthusiasts
- Format:Print
- Focus:Hands-on automata making
- Language:English
Our verdict“This book is ideal for creative hobbyists and artisans focused on making automata with practical, easy-to-follow guidance.”
Cabaret Mechanical Movement: Understanding Movement and Making Automata
This volume provides a well-rounded introduction to mechanical movement and automata, with practical instructions suitable for newcomers and experienced creators alike. Compared to the first Cabaret Mechanical Movement entry, this edition emphasizes accessible guidance and beginner-friendly content, making it easier to grasp fundamental principles and craft basic automata. Its comprehensive instructions and illustrations make it approachable, although it lacks detailed technical specifications or advanced manufacturing tips. It’s an excellent starting point for those new to automata or hobbyists expanding their skills.
Pros:- Clear, practical instructions suitable for beginners
- Includes helpful illustrations and guidance
- Versatile for hobbyists and artists new to automata
Cons:- Limited technical details or specifications
- Lacks advanced or specialized content for experienced practitioners
Best for: Beginners and hobbyists interested in automata craftsmanship with practical, approachable guidance
Not ideal for: Advanced practitioners or engineers seeking detailed technical or mechanical design data
- Type:Beginner-friendly guide
- Content:Automata principles and practical techniques
- Audience:Hobbyists, beginners, automata enthusiasts
- Format:Print
- Focus:Basic automata creation
- Language:English
Our verdict“This book makes a perfect starting point for beginners and hobbyists eager to learn automata making with accessible guidance.”
100+ Mechanical Movements: An Illustrated Guide to Mechanical Mechanisms
This book earns its place as the best visual reference for those seeking a clear, illustrated overview of over 100 mechanical movements. Unlike the dense, text-heavy 507 Mechanical Movements: Mechanisms and Devices, it emphasizes detailed illustrations that make complex mechanisms easier to understand at a glance. However, it doesn’t include practical applications or step-by-step instructions, which makes it less suitable for hands-on projects. This guide is ideal for enthusiasts, students, or designers who need a comprehensive visual catalog rather than a technical manual. The focus on over 100 mechanisms ensures broad coverage, but the lack of applied content might disappoint readers looking for how to build or utilize these movements practically.
Pros:- Extensive collection of over 100 illustrated mechanisms
- Clear, detailed diagrams enhance understanding
- Suitable for visual learners and design professionals
- Compact format makes it easy to browse
Cons:- Lacks practical application or construction guidance
- No accompanying explanations on how to implement mechanisms
Best for: Mechanical engineering students or hobbyists who need a detailed visual catalog of mechanisms
Not ideal for: Practitioners seeking step-by-step instructions or practical building guides
- Number of Mechanisms Covered:Over 100
- Illustrations:Detailed diagrams
- Intended Audience:Enthusiasts, students, designers
- Content Type:Illustrated overview
- Format:Hardcover/Paperback
- Page Count:Approx. 200 pages
- Publication Year:Latest edition
- Publisher:Unknown
Our verdict“This book is perfect for visual learners and enthusiasts who want a comprehensive illustrated reference rather than a practical manual.”
How We Picked
The selection process focused on a combination of factors that matter most to readers interested in mechanical movements. We evaluated each book based on its technical accuracy, clarity of diagrams and explanations, breadth of content, and user accessibility. Additional considerations included the book’s historical significance, practical application, and overall value. Books that balanced detail with readability ranked higher, while overly specialized or overly simplified titles were rated lower. Our ranking reflects the books that best serve a diverse range of learners, from beginners to experts.| mechanical movement book | Format |
|---|---|
| Five Hundred and Seven Mechani | Hardcover |
| 507 Mechanical Movements: Mech | Hardcover or paperback |
| 507 Mechanical Movements: Mech | Hardcover |
| 1800 Mechanical Movements | Paperback |
| Making Things Move: DIY Mechan | Paperback |
| Engineer’s Sketch-Book of Mech | Print only |
| Mechanisms and Mechanical Move | |
| 507 Mechanical Movements | |
| Cabaret Mechanical Movement: U | |
| Cabaret Mechanical Movement: U | |
| 100+ Mechanical Movements: An | Hardcover/Paperback |
Factors to Consider When Choosing Best Mechanical Movement Books
Choosing the right mechanical movement book depends on your experience level, learning goals, and specific interests. Consider whether you want a detailed technical reference, a historical perspective, or a practical DIY guide. The following factors will help you identify the best fit for your needs and avoid common pitfalls like overpaying for unnecessary depth or selecting a book that’s too simplified.Level of Detail and Technical Depth
Determine whether you need a highly detailed reference with precise diagrams and mechanisms or a more accessible intro that covers fundamentals. Advanced readers should look for books with comprehensive illustrations and technical explanations, while beginners benefit from simplified language and step-by-step projects. Picking a book that matches your current knowledge prevents frustration and accelerates learning.
Illustrations and Visual Aids
Clear, well-labeled diagrams are essential when studying mechanical movements. Look for books that prioritize visual clarity, as complex mechanisms can be difficult to grasp through text alone. Books with color-coded parts or multiple views often make it easier to understand how mechanisms work in real life, reducing the need for supplementary materials.
Scope and Coverage
Some books focus exclusively on specific types of mechanisms, while others provide broad overviews. Consider your interest—are you after a comprehensive encyclopedia or a focused guide on automata or clockwork? A wider scope adds value if you want a versatile reference, but targeted books can be more practical for specific projects or hobbies.
Practical Application and Projects
If you plan to build or experiment with mechanisms, choose books that include DIY projects and step-by-step instructions. These practical guides help translate theory into hands-on skills, making complex concepts more approachable. Beware of overly theoretical books if your goal is learning through doing, and vice versa.
Price and Value
High-quality, detailed books tend to cost more, but they often provide long-term value as reference materials. Cheaper titles might be suitable for casual learners or beginners but may lack depth or accuracy. Consider your budget alongside your learning goals to select a book that offers the best balance of quality and affordability.
Frequently Asked Questions
Is it better to buy a historical or modern book on mechanical movements?
Choosing between historical and modern books depends on your focus. Historical books, like ‘Five Hundred and Seven Mechanical Movements 1908,’ offer detailed insights into classic mechanisms and foundational principles, making them invaluable for deep understanding. Modern books often incorporate updated terminology, contemporary applications, and practical DIY projects, which can be more engaging and accessible for beginners and hobbyists. Both types have their strengths, so consider your goals—if you want a technical reference, historical works are excellent; for hands-on learning, modern guides may be preferable.
Are illustrated books more helpful than text-heavy ones?
Illustrations significantly enhance comprehension, especially for visual learners, by clarifying complex mechanisms that are difficult to grasp through words alone. Well-detailed diagrams, exploded views, and color coding can transform abstract concepts into tangible understanding. However, highly illustrated books can sometimes sacrifice depth for clarity, so it’s best to find a balance—look for books that combine comprehensive explanations with quality visuals. Avoid overly schematic diagrams that lack labels or annotations, as they can be confusing rather than helpful.
Can I use these books for DIY automata projects?
Many of these books are suitable for DIY automata and mechanical art projects, especially those that include practical instructions, diagrams, and construction tips. Titles like ‘Cabaret Mechanical Movement’ focus specifically on automata, making them ideal for hobbyists interested in creating moving sculptures. For best results, select books that provide step-by-step guides and materials lists, ensuring you have the necessary resources to bring your ideas to life. Be mindful that highly technical books may be too complex for casual craft projects, so match the book’s scope to your skill level.
How do I choose a book if I want to learn about clockwork mechanisms?
If clockwork mechanisms are your focus, seek out titles that cover gear trains, escapements, and winding mechanisms in detail. Books that emphasize practical applications, such as clockmaking or watchmaking, tend to include relevant mechanisms and assembly instructions. Consider whether the book offers real-world examples or historical context, which can deepen your understanding. For novices, a beginner-friendly guide that explains basic gear ratios and power transmission is more suitable, while experienced readers may prefer advanced texts with technical schematics.
Is a more expensive book always better?
Not necessarily. While higher-priced books often contain more detailed content, better illustrations, and comprehensive coverage, they are not automatically the best choice for every reader. If you’re a beginner or only need a general overview, a more affordable, straightforward book may suffice. Conversely, for professional or advanced study, investing in a well-reviewed, detailed reference can save time and improve understanding. Always consider your current skill level and goals before committing to a higher price point.
Conclusion
For most readers, the best overall choice is a versatile, well-illustrated book that balances depth with clarity. If you seek long-term value, a comprehensive reference like ‘Five Hundred and Seven Mechanical Movements’ suits professionals and enthusiasts alike. Beginners should consider accessible guides with practical projects, such as ‘Making Things Move,’ which make learning engaging. For hobbyists interested in automata, specialized titles like ‘Cabaret Mechanical Movement’ provide focused insights. Budget-conscious buyers can find quality options among mid-range titles, while those with advanced needs should look for detailed, technical works that serve as definitive references.
