There are many resources available on the net that are in the public domain, and therefore freely usable without restrictions for Wikimedia universe (this includes Wikibooks) content.
There are also many copyrighted resources whose licensing terms are liberal enough that they can generally be used as well. For these, see free or semi-free non-Public-Domain information resources and GNU Free Documentation license resources (includes images).
This page is intended as a list of only true public domain text resources. For public domain images, see public domain image resources.
CAVEAT: Because there is no concept of public domain in Japan's copyright law, even though the materials are claimed public domain, there can be some restrictions such as about commercial use, which has a conflict with GFDL. Also, unlike the United States, most English speaking commonwealth countries exert Crown copyright. Please make certain that in any particular jurisdiction government agencies will allow you to copy materials without permission.
India government sites also seem to be copyright by default. Quoting from : Unless otherwise stated, copyright and all intellectual property rights in all material presented on the site (including but not limited to text, audio, video or graphical images), trademarks and logos appearing on this site are the property of Government of Maharashtra and are protected under applicable Indian laws. Any infringement shall be vigorously defended and pursued to the fullest extent permitted by law.
Please don't data dump!
The resources below are valuable, but many are very old, context-dependent, written from biased points of view, and otherwise are not in themselves good encyclopedia articles. The 1911 encyclopedia discussed below is a good example of this - it contains some useful information, but also antiquated writing style and innumerable errors of fact.
So please, if you copy material from these sources, make sure you take some time to verify the actuality of the information, edit, update, introduce, or otherwise produce a good article out of it rather than just dumping it here verbatim. But if you can't do that, put it in anyway because somebody else will come by and tweak it. Wikibooks books are living texts, because everybody has the power to edit them. An entry that starts out incorrect, as a stub or even as something very inane will eventually be tweaked and evolve into something much more sophisticated.
Encyclopedic or general resources
- Most publications of the United States Federal Government. Under the Federal Copyright Act material that is originated by the Federal government is not subject to copyright. In some cases, material may originate with a private contractor which assigns the copyright to the agency. However, material that is generated by the Federal government which doesn't have a notice can be copied. Entries below marked "(US Federal Govt.)" belong to this category. Note this only applies to the *Federal* government. United States state governments can copyright materials.
- While the Canadian government claims Crown copyright there are images archives at the National Library of Canada that are in the public domain. They include:
- Hypertext Webster Gateway A searchable interface to a 1913 public-domain Webster's dictionary, downloadable here: Public Domain Dictionary
- Project Gutenberg See in particular The Project Gutenberg Encyclopedia (although only Vol 1 of this seems to be available). Note that not all of the Project Gutenberg text are fully in the public domain. Read the license of the respective texts carefully.
- 1911 Encyclopedia A scanned version of the 1911 Encyclopædia Britannica. The OCR quality is not very high. Some articles end in the middle and continue on the next page. The writing style is antiquated and archaic, contains a fair amount of bias, and the material contains many factual errors. Anything taken from here needs extensive fact-checking and editing. See Wikipedia:1911 Encyclopaedia Britannica for ways of best using this material.
- The Household Cyclopedia
- The Catholic Encyclopedia (1908)
- The Jewish Encyclopedia (1901-1906)
- This website contains the complete contents of the 12-volume Jewish Encyclopedia, which was originally published between 1901-1906. The Jewish Encyclopedia, which recently became part of the public domain, contains over 15,000 articles and illustrations. This online version contains the unedited contents of the original encyclopedia. Since the original work was completed almost 100 years ago, it does not cover a significant portion of modern Jewish History (e.g., the creation of Israel, the Holocaust, etc.). However, it does contain an incredible amount of information that is remarkably relevant today.
- We are considering inviting the Internet community to help us update the encyclopedia -- if you are interested in volunteering (as a writer, editor, etc.) please join our Mailing List. By putting this important work on the Internet, we hope to improve the quality of Jewish information available online -- and stimulate new discussion. Therefore, we have sections "Discussion Forums" and "Internet Links" which allow our visitors to converse and identify related websites.
- ibiblio.org is a major repository of information, "the public's library and digital archive". All collections on ibiblio are assumed to be in the public domain unless otherwise noted. Check for copyright notices on any material you wish to use.
- Web sites that contain collections that are copyright free - a lot of duplication here but it might be some are new.
- A Pronouncing dictionary of Biography and Mythology. Contains a large number (10000+) short NPOV biographical entries many of which could be copied and pasted to form stubs (due to its focus it contains information on many 19th and 18th century figures not yet covered in Wikibooks).
- What resources are available in the Public Domain? - Northern Arizona University.
Philosophy, mathematics and natural science
Astronomy and astrophysics
- (US Federal Govt.) Space Educators' Handbook
- (US Federal Govt.) NASA glossary of terms - appears to be in the PD, please check
- (US Federal Govt.) NASA DICTIONARY OF TECHNICAL TERMS FOR AEROSPACE USE (originally NASA report SP-7, written in 1965, some pages updated since then: may not be fully up-to-date)
- (US Federal Govt.) US Forest Service Fire Effects Database Database of current information on a wide variety of tree, shrub, grass, mammal, bird, reptile and amphibian species found largely in North America -- great reference material
Note: Phenethylamines I Have Known And Loved i.e.: PIHKAL and TIHKAL, formerly listed here, are not in the public domain, so cannot be listed here
Geology and Earth science
- (US Federal Govt.) USGS Mineral Resources Program - "The Mineral Resources Program provides and communicates current, impartial information on the occurrence, quality, quantity, and availability of mineral resources."
- (US Federal Govt.) NASA GISS glossary of climate terms
- (US Federal Govt.) NASA Earth Observatory Glossary
- (US Federal Govt.) Geodesy for the Layman
- biographies of mathematicians - from a 1908 history of mathematics. See the discussion at Rouse History of Mathematics
- Relativity: The Special and General Theory by Albert Einstein
- Physics for Free has three public domain physics books by former Yale professor Frank Firk. One about basic physics, one about groups and particles and one about Einstein's theories.
Geography and maps
- (US Federal Govt.) U.S. Census Bureau Has an enormous range of facts and figures which we will find helpful in fleshing out articles about cities and states.
- (US Federal Govt.) Summary Demographic Data by Country from the US Census Bureau
- (US Federal Govt.) CIA World Factbook Contains basic facts on all the countries of the world.
- (US Federal Govt.) U.S. State Dept.: Background notes on the countries of the world. Also see their copyright notice, which, as you'll see, places material that is not explicitly copyrighted in the public domain.
- (US Federal Govt.)  - Library of Congress area country studies. It explicitly states that it is not copyrighted
- (US Federal Govt.) the NIMA www.nima.mil GEOnet Names Server contains approximately 3.88 million named geographical features outside the United States, with 5.34 million names 
- (US Federal Govt.) the USGS Geographic Names Information System claims to have almost 2 million physical and cultural geographic features within the United States
- Perry–Castañeda Library Map Collection at the University of Texas (Check Usage statement and verify public domain status.)
- (US Federal Govt.) United States National Archives and Records Administration, the U.S. federal government's official archive site
- Historical Maps of the Perry–Castañeda Library Map Collection at the University of Texas (Public domain usage statement - "Courtesy of The General Libraries, The University of Texas at Austin.")
- (US Federal Govt.) Biographical Directory of the United States Congress - biographical information on everyone who ever served in Congress, including a good number of presidents
History of science and technology
Language and Linguistics
- (US Federal Govt.) Library of Congress Country Studies An on-line version of the Library of Congress Country Studies with information on 101 countries, including detailed histories. See Library of Congress Country Studies for ways on using this material.
- Classics in the History of Psychology is a collection of classic public domain works in psychology collected by Christopher D. Green: see here for a note about the copyright status of the individual documents in the collection.
Applied arts and sciences
Business and industry
- (US Federal Govt.) US Energy Information Agency - statistics and info on energy industry (mostly US but some stuff for the world) - they appreciate but do not require acknowledgement (copyright info here)
- (US Federal Govt.) Federal Standard 1037C, a telecommunications glossary, appears to be mostly in the public domain based on these principles, and is a source of a large number of bits of useful material. A few items are derived from copyrighted sources: where this is the case, there is an attribution to the source. Note: only those articles that have substantial content and are from 100% public domain sources are appropriate to be used in Wikibooks
- (US Federal Govt.) DISA site about commercial telecommunications standards From the site: "This site is maintained by the Commercial Standards Division of the Defense Information Systems Agency (DISA) to provide information about the current status of commercial telecommunications standards."
- (US Federal Govt.) NIST Dictionary of Algorithms, Data Structures, and Problems: Huge, high-quality resource. All entries are in the public domain except for a few that carry an explicit copyright notice.
- Public domain lecture notes: "Introduction to Computer Science", "Data Structures" and "Analysis of Algorithms"
- The Jargon File Eric S. Raymond's definitive work on geek-speak.
- (US Federal Govt.) Occupational Outlook Handbook Contains descriptions of a great many occupations.
- (US Federal Govt.) Centers for Disease Control and Prevention "In general all information presented in these pages and all items available for download are for public use. However, you may encounter some pages that require a login password and id. If this is the case you may assume that information presented and items available for download therein are for your authorized access only and not for redistribution by you unless you are otherwise informed."
- (US Federal Govt.) Medline at the NIH copyright terms here indicating materials in public domain unless indicated otherwise
- (US Federal Govt.) NIH public domain publications on urology
- (US Federal Govt.) NIMH Patient education materials (Public Domain)
- (US Federal Govt.) USDA Nutrient Data Laboratory Contains nutritional information on loads of foods. (From FAQ), "USDA food composition data is in the public domain and there is no copyright. We would appreciate it if you would list us as the source of the data and when possible we would like to see the product which uses the data or be notified of its use."
- (US Federal Govt.) A large collection of public domain information sheets on various neurological disorders
- Note: This Google search for "nih publication "not copyrighted" site:.gov" should help uncover more NIH public domain documents
- University of Cincinnati etexts: Contains a nice edition of 1918 Gray's Anatomy with illustrations.
- (US Federal Govt.) U.S. National Toxicology Program: copyright notice here, typical U.S. govt terms.
- The Bad Bug Book at http://www.cfsan.fda.gov/~mow/intro.html appears to be in the public domain: but please check each section individually for public domain status.
- Asthma genetics - Public domain data
- (US Federal Govt.) Mental Health: A Report of the Surgeon General (needs positive confirmation before use: some diagrams within the text say "used by permission", which implies that they are copyrighted -- however, the rest appears to be written by U.S. govt employees)
- (US Federal Govt.) The NCI thesaurus is a massive public domain repository of definitions of medical terms
- (US Federal Govt.) Federal Emergency Management Agency: Not sure how much of this is useful, but anyway it's under the same terms as the U.S. Department of State site: all in the public domain unless it carries an explicit copyright notice.
- (US Federal Govt.) U.S. Environmental Protection Agency: copyright notice here, typical U.S. gov't terms. Does have some good information for people patient enough to find it.
- (US Federal Govt.) Voice Of America - All text, audio and video material produced exclusively by the Voice of America is public domain. However, some images and graphics are licensed for use and covered by all applicable copyright laws.
- UNESCO Public Domain Resources and Virtual Library at this URL
Arts and Entertainment
- Harpers Dictionary of Classical Antiquities (1898) can be found via http://www.art.man.ac.uk/clah/links/searchency.htm
- Bulfinch's mythology from project Gutenberg
- US Department of Agriculture Food Safety and Inspection Service maintains many articles about meat products.
- Online Book Initiative
- Public Domain Reader: Public domain works in HTML, PDF, iSilo .pdb, Rocket eBook .rb and Plain text formats.
- The Online Books Page: A comprehensive index of books available on the Internet. Most are public domain, but not all; check for copyright restrictions.
- Public Book Shelf
- Brewer's Reader's Handbook, published in 1898, states that "the object of this Handbook is to supply readers and speakers with a lucid but very brief account of such names as are used in allusions and references, whether by poets or prose writers". Contains many short articles, some on obscure topics.
- The Choral Public Domain Library describes itself as 'A Free Sheet Music Archive'
- Mutopia: a collection of public domain sheet music.
- Project Gutenberg music section
- Biblical dictionaries: Some late nineteenth century Biblical dictionaries; these might need work to render unbiased and up to date.
- A number of articles already contain most of the useful text from Easton's Bible Dictionary (1897)
- Hitchcock's Bible Dictionary's list of Biblical names has been used as a source for the List of Biblical names.
- Smith's Bible Dictionary is another 19th century Bible dictionary, with much useful but dated text
- Public Domain Biblical references
- Christian Classics Ethereal Library: A project similar to Project Gutenberg, but focusing on Christian texts.
- American Standard Version of the Holy Bible (1901)
- King James Version of the Holy Bible with Apocrypha
- Please see public domain image resources.
- Writings by Greg Goebel: Science, technology, military history, introductions to classical and relativistic physics.
- Infoanarchy: a weblog dedicated to copyright issues. All original material is in the public domain, although some redistributed articles may be under copyright.
- "Ethical treatment for all youth", a website that documents therapy and detention of children and juveniles for consensual sexual activity. Author wrote to me in a personal email: "Certainly, I intend everything at my site to be in the public domain, to be used freely by anyone else. Of course, I would appreciate it if people who use it would link to my site, since I can use all the exposure I can get."
To be filed
please file these resources under the appropriate topic headings above
- There are no more entries to be filed at the moment
Sources for finding public domain resources
Here are some web searches which may help discover U.S. Federal Government and other public domain documents. Please note that you must still manually verify that documents are in the public domain. Please note that not all sites in the .gov domain are U.S. federal government sites: some may be U.S. state or other local government sites.
- This Google search for '"not copyrighted" site:.gov' finds documents on websites in the .gov domain that contain the text "not copyrighted".
- This Google search for '"public domain" site:.gov' finds documents on websites in the .gov domain that contain the text "public domain".
Google searches for links or exact phrases:
- "this document is in the public domain" (estimated 2500+ hits)
- "this page is in the public domain" (estimated 1000+ hits)
- "this information is in the public domain" (extimated 1000+ hits)
- "this text is in the public domain" (estimated 2000+ hits)
- "placed in the public domain" (estimated 24000+ hits, but many instances refer to other things)
- "www.primarilypublicdomain.org" (find links confirming that a site is Primarily Public Domain)
- Creative Commons Public Domain Dedication
The Creative Commons initiative may become a valuable new resource for Wikibooks authors. The project provides a "wizard" for licensing information under various open content licenses (including the public domain, which is not a license), and also features a directory of these works. (See also Creative Commons License)
- The Public Domain: How to Find & Use Copyright-Free Writings, Music, Art & More by Stephen Fishman, ISBN 0873374339
Lists of general resources:
- Registry for material that is in the public domain "except as noted"
- Open People network for people adding original content, in the locations they specfiy, in the Public Domain except as noted
- Unmaintained list of public domain resources by Kevin Savetz
- Banis Associates list of public domain resources
- Public Domain Music website
- Brian Waters' list of public domain resources
- New General Catalog of Old Books and Authors tracking old books and author's dates for determining copyright expiration
Lists of U.S. Government resources:
- Index of Federal Specifications, Standards and Commercial Item Descriptions
- Federal Information Processing Standards home page
- DOD Index of Specifications and Standards
- Department of Defense Single Stock Point for MilSpecs and Standards
- NIST Data Resources index
- Catalog of U.S. Government Publications
- Country Study - copyright free