What is "prior art"?

Prior art is defined by statute (35. U.S.C. 102), but it may generally be thought of as anything that previously exists in the public domain. Prior art may include printed publications, conference handouts (and sometimes even presentations within a University), books, web postings, newspaper articles, and awarded NIH grants. Prior art is often designated regardless of where the material was published or in what language it was published. Prior art may also include orally presented material, such as discussions at conferences, disclosures to competitors, certain disclosures to colleagues in a field, and other public statements. Inventors may under certain circumstances create prior art against themselves (thereby jeopardizing patent rights) by publicly disclosing an invention prior to the filing of a patent application.