The Day After Roswell is an American book about extraterrestrial spacecraft and the Roswell UFO incident. It was written by United States Army Colonel Philip J. Corso, with help from William J. Birnes, and was published as a tell-all memoir by Pocket Books in 1997, a year before Corso's death. The book claims that an extraterrestrial spacecraft crashed near Roswell, New Mexico in 1947 and was recovered by the United States government who then sought to cover up all evidence of extraterrestrials.
The majority of the book is an account of Colonel Corso's claims that he was assigned to a secret government program that provided some material recovered from crashed spacecraft to private industry (without saying where the items came from) to reverse engineer them for corporate use. The book contends that several aspects of modern technology such as fiber optics and computer chips were developed by using information taken from the craft.