Backed by documents newly declassified through the Freedom of Information Act, Col. Philip J. Corso (Ret.), former head of the Foreign Technology Desk at the U.S. Army's Research & Development department, reveals for the first time his personal stewardship of alien artifacts from the 1947 Roswell crash, and discloses the U.S. government's astonishing role in the Roswell incident: what was found, the cover-up, and how these alien artifacts changed the course of 20th-century history. Photo insert.