Copyright is a legal term defining the ownership of Intellectual Property.
 Copyright Rules
Works not in the public domain are considered to be copyrighted. An author or owner of a copyright determines what can be done with a document. An author can choose to place their work in the public domain or may choose any of several alternatives such as the GNU copyleft agreement or the Creative Commons license.
Breaking a copyright agreement is considered to be different from other forms of theft for example:
The United States Supreme Court doesn't agree that breaking a copyright is stealing. (Dowling v. US, 473 US 207):
Since the statutorily defined property rights of a copyright holder have a character distinct from the possessory interest of the owner of simple "goods, wares, [or] merchandise," interference with copyright does not easily equate with theft, conversion, or fraud. The infringer of a copyright does not assume physical control over the copyright nor wholly deprive its owner of its use. Infringement implicates a more complex set of property interests than does run-of-the-mill theft, conversion, or fraud.
Out-of-copyright books account for about one-sixth of all titles. Most books--75 percent of them--are in copyright, but out of print. Only about 10 percent of all books are both copyrighted and in print. --According to the WeeklyStandard.
See below for What Is In the Public Domain.
 What can be copyrighted
This document is not legal advice. Check with a copyright attorney if you have questions on what can be copyrighted.
In general those items called intellectual property can be copyrighted. Other items may be trademarked. Copyrighted items include:
- Books, documents, and other writings.
- Pictures, images, paintings, photographs
- translations of a book, even if the original is in the pubic domain.
Note that a book or eBook can have multiple copyright owners. For example illustrations, the cover, and included fonts can be separately copyrighted from the writings. Different portions of a book can have separate owners.
Generally you cannot copyright:
- information - A telephone book cannot be copyrighted.
- Someone else's work, unless you purchase the copyright. Copyright ownership can be transferred in a will.
- Changing the format, correcting errors, or beautifying of a public domain document or book.
 Copyright claim
Many times you may see a copyright claim on a book that is clearly in the public domain. It is not illegal to make such a claim but it is not enforceable. The copyright claim can be listed on a public domain book for unique items that have been created that are part of the book as published. The copyright extends only to those unique items and if a person copies the text of the pubic domain portion he/she has not violated the copyright.
 What Is In the Public Domain
What is in the public domain? As you might expect, it's somewhat complicated. For an item posted on a web site, it is the location of the web site that is used to follow the Public Domain rules. The owner of this web site is a Swiss citizen and to limit his liability MobileRead now follows the Swiss rule of Pubic Domain which is defined as 70 years after the death of the author. This applies to all new submissions on MobileRead.
 The world
In most of the world, it's pretty straightforward - things enter the public domain (PD) a certain number of years after the death of the author. In most countries that number is 70 years, in a few (e.g. Canada) it's 50. That means that, for example, all works of authors who died prior to 1943 are currently PD in Europe; prior to 1963 in Canada, and that advances, year by year, as you would expect.
Australia's a bit different. It changed from lifetime+50 to lifetime+70 in 2005. All works by Authors who died before 1955 are out of copyright in Australia. Works by authors who died in 1955 won't be out of copyright until 2026, like in other lifetime+70 countries.
 The U.S.A.
In the U.S., the rules are more complicated. Full details of the rules can be found, off site, at Cornell.
A general overview for works published in the U.S.:
- Anything published prior to 1923 is PD.
- Anything published from 1923 to 1978 without a copyright notice is PD.
- Anything published from 1978 to 2 March 1989 without a copyright notice or subsequent registration is PD
- Anything published from 1923 to 1963 for which copyright was NOT renewed, is PD. To check for this visit Copyright Renewal Records.
- Anything published from 1923 to 1963 for which copyright WAS renewed, is in copyright until 95 years after publication (i.e. 2019 and later).
- Anything published from 1964 to 1977 is in copyright until 95 years after publication (i.e. 2060 and later) There is a PDF document that lists these books. Use the link below to find it.
- Anything published after 1977 is in copyright until 2048 or author's death + 70 years, whichever is longer, or for 95 years after publication for corporate works. To search for a particular book visit the United States Copyright Office's Web Voyage.
- Anything published after 2002 is in copyright until 70 years after the author's death, or for 95 years after publication for corporate works.
- One exception is U.S. government publications which are always in the Public Domain.
- Unpublished anonymous or corporate works, or works where the date of the author's death is unknown, are copyright for 120 years from date of creation.
The net result of this is that some items are in the PD in the U.S., but not elsewhere (early works of authors who had long lives - e.g., Agatha Christie), and other things are PD outside the U.S. but not in the U.S. (e.g., works of authors published after 1923, who died before 1938/1958).
As the years go by, the balance is shifting - what is PD in the U.S. is a static set of works, whereas elsewhere new material is entering the PD every year.
The earliest that any new works will enter the Public Domain in the U.S. is 1st January 2019, when works first published in 1923 enter the public domain. This is assuming there isn't another copyright amendment act in the next ten years that extends U.S. copyright further.
 For more information
Each country is different so a check with official information regarding your country is something each person concerned with copyright should do. A google search can usually turn up all the information you need.
- Canada copyright law can be seen at: Canada copyright - an interpretation
- http://www.mobileread.com/copyright.html - For the official policy of MobileRead
- Stanford copyright renewal database
- A distilled version of the US copyright law
- Cornell University explanation
- http://www.booksandwriters.co.uk/ - short biographies and other data to help determine copyright.