The public domain (PD) consists of all the creative work to which no exclusive intellectual property rights apply. Those rights may have expired, been forfeited, expressly waived, or may be inapplicable. Because no one holds the exclusive rights, anyone can legally use or reference those works without permission.
Newton's own copy of his Principia, with hand-written corrections for the second edition
Visual created for Public Domain Day. Features Leonardo da Vinci's Mona Lisa, as it is famously part of the public domain
Intellectual property (IP) is a category of property that includes intangible creations of the human intellect. There are many types of intellectual property, and some countries recognize more than others. The best-known types are patents, copyrights, trademarks, and trade secrets. The modern concept of intellectual property developed in England in the 17th and 18th centuries. The term "intellectual property" began to be used in the 19th century, though it was not until the late 20th century that intellectual property became commonplace in most of the world's legal systems.
Intellectual property laws such as trademark laws forbid the sale of infringing goods like these "McDnoald's" [sic] and "NKIE" [sic] sandals from China.
The Statute of Anne came into force in 1710.
Demonstration in Sweden in support of file sharing, 2006
"Copying is not theft!" badge with a character resembling Mickey Mouse in reference to the "in popular culture" rationale behind the Sonny Bono Copyright Term Extension Act of 1998