This archive contains a collection of scanned original documents and audio recordings related to Hugh Everett III, who first proposed what has come to be known as the many-worlds interpretation of quantum mechanics.These documents include draft and final versions of Everett’s long and short Ph.D. theses and the early notes that led to these published works, Everett’s correspondence regarding his relative state formulation of pure wave mechanics, and miscellaneous biographical material. Most of these documents were discovered in the basement of Mark Everett, Hugh Everett III’s son in 2007. This collection was edited by Jeffrey A. Barrett, Peter Byrne, and James O. Weatherall.