"Nonfiction authors often use existing materials in their works: A historian excerpts a soldier’s letters to a loved one; an art critic reproduces a telling detail in a painting; a scientist quotes from a well-known article. Readers of nonfiction works expect new writing to reference and incorporate other works; indeed, the quality and integrity of nonfiction works frequently depend on the author’s skillful use of such materials. Although drawing from other works is common, it can often seem difficult to know when (and how much) unlicensed copying is permissible and whether certain unlicensed uses of another’s work put you at risk of copyright infringement. Sometimes, authors need to seek permission or pay for a license to use copyrighted materials. An author may even need a license to use her own works because she signed over her copyrights to her publisher. But not always. In some situations, unlicensed use may be legally permitted by virtue of the “fair use” doctrine, a well-known (but oft-misunderstood) limitation to copyright in the United States. Fair use is a powerful tool, but unfortunately many nonfiction authors find it tricky to know when to rely on fair use and when to seek permission. That’s where this guide comes in. In addition to providing background information on copyright law and fair use, this guide identifies three common situations that nonfiction authors encounter when incorporating existing materials into their works and then discusses general fair use principles and limitations that apply in these situations. This guidance is based on broadly shared norms found in the leading fair use statements of best practices, as well as existing case law." (Introduction)