The following FAQ is designed to answer your questions about our PDFs.

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• May I share my PDF with others?

• Are all books available in PDF format?

• How do I download PDF files?

• What is a PDF file?
• What software do I need to read a PDF?
• What hardware is necessary for reading PDFs?
• What browser should I use?
• How long will it take for me to download a PDF file from your Web site?
• What's the best strategy if I'm on a very slow, bad line?
• Where should I download these files?
• How do I view or print my downloaded files?
• Why are some PDF files on your site searchable and others are not?

May I share my PDF with others?

All of the National Academies Press books (electronic and printed versions) on this website are copyrighted by the National Academy of Sciences with all rights reserved. You may not distribute, post, or copy our work without written permission from the National Academies Press. Posting or distributing our PDF files not only violates our copyright but it also could proliferate the sharing of non-authoritative versions of our reports.

We encourage sharing our books via approved means to help to maximize the impact of our work. Please use the following methods to ensure that everyone receives up-to-date, authoritative files directly from the National Academies Press servers.

• Point your colleagues to the book's unique URL indicated above. Example: www.nap.edu/catalog/12614.html. Each book will have a different number prior to .html.


• Use the widget on the book's catalog page for posting on your Website. The widget will allow people to download the PDF for free without leaving your site but will pull the file from our servers, ensuring an authoritative version.


• Click the share button on the book's catalog page to conveniently access the tools to tell your colleagues about the book and point to its free PDF file.


• Connect the book with your friends and colleagues via facebook and twitter buttons found on the book's catalog page.

Please see our terms of use statement for additional information

For questions about copyright and reuse for people other than National Academies staff, go to http://books.nap.edu/reprint_permission.html. For internal staff wishing to reuse content, please refer to the Managing Intellectual Property policy or contact your NAP sponsoring editor.

*There are a small number of older reports that never had PDF files and therefore, those reports are not available for download. In addition, there are contractual requirements that preclude NAP from offering some PDF files for free. Those include the series "Nutrient Requirements of Domestic Animals" and books in the Joseph Henry Press imprint. Reports from the Transportation Research Board are available in various formats on their site—www.trb.org.

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Are all books available in PDF format?

The National Academies Press is proud to be one of the only online bookstores that provides anyone in the connected world with free page-by-page access to all of our books. We began doing this in 1996.

As of June 1st 2011, PDFs of reports that were previously for sale on the National Academy Press (NAP) Website and PDFs associated with future reports will be offered free of charge to all Web visitors.

There are a small number of reports that never had PDF files and therefore, those reports are not available for download. In addition part of the series, "Nutrient Requirements of Domestic Animals" are not be available in PDF and future titles in this series will also not have PDFs associated with them.

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How do I download PDF files?

You may download PDF files from the National Academies Press either by A) creating an account or B) as a guest.

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What is a PDF file?

PDF is an acronym for Portable Document Format. The PDF file format created by Adobe Systems, Inc. is a self-contained cross-platform document. In plain language, it is a file that will look the same on the screen and in print, regardless of what kind of computer or printer someone is using and regardless of what software package was originally used to create it. Although they contain the complete formatting of the original document, including fonts and images, PDF files are highly compressed, allowing complex information to be downloaded efficiently.

What software do I need to read a PDF?

Each PDF book or chapter on our Web site may be downloaded to your computer, viewed, and/or printed out using Acrobat Reader from within a browser or as its own application.

What hardware is necessary for reading PDFs?

You may use the Adobe Reader as a standalone program to read these books or chapters. However, most people will likely use the built-in Adobe Reader viewer within Internet Explorer, Firefox, or other popular Internet browsers.

What browser should I use?

You may use the Adobe Reader as a standalone program to read these books or chapters. However, most people will likely use the built-in Adobe Reader viewer within Internet Explorer, Firefox, or other popular Internet browsers.

How long will it take for me to download a PDF file from your Web site?

The time it will take you to download our PDF files depends on the type of connection you have and the size of the book. The following table provides estimated times.

What's the best strategy if I'm on a very slow, bad line?

In that case, try downloading individual chapters (instead of the entire book), or start the whole-book download at the end of the day, before you go to sleep, and let it download overnight.

Where should I download these files?

We recommend creating a special folder just for your books, and downloading to that folder. We do not recommend downloading to a floppy drive.

How do I view or print my downloaded files?

To view or print your downloaded files, you must have a PDF reader such as Adobe Reader or Mac Preview loaded on your computer. In Windows Explorer, Mac Finder or other file management program, locate the drive and folder where you downloaded your files and double click on the filename. At that point, your default PDF-reading program will open and display your PDF file for viewing. To print the file, use the printing function in the application.

Why are some PDF files on your site searchable and others are not?

The majority of the PDF files on our site are fully searchable. They are called "native" PDF files and are created from source files. A few of the PDF files are created from pictures of the pages, and are called "scanned image" PDF files. These are very large and are not searchable. We create this type of PDF when no source files are available.

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