Philip J. Corso was an American U.S. Army officer who served in military intelligence and later worked in the Pentagon’s Foreign Technology Division. His documented career included World War II service, staff assignments, and work connected to technology assessment during the Cold War.

Corso served in Army intelligence and staff positions across the Second World War, the occupation of Europe, Korea, and the Cold War. He later worked in the Pentagon under Lieutenant General Arthur Trudeau before retiring and entering civilian roles. That documented career gave his late memoir an aura of institutional access. It also meant the book arrived after many potential witnesses had died and decades after the alleged technology-transfer work, leaving historians to compare a dramatic personal account with a sparse contemporaneous record.

In the 1997 book The Day After Roswell, written with William Birnes, Corso claimed that he handled material recovered from the 1947 Roswell incident and helped seed it into private industry. He linked the alleged program to technologies such as integrated circuits, fiber optics, and night vision. Historians of those technologies document conventional research paths that predate or do not require Corso’s account, and no authenticated chain of custody for alien material has been released.

Corso is a foundational reverse-engineering claimant. His real military résumé gave the memoir unusual influence, while publication late in life and the absence of program records leave its core allegations unresolved. His biography separates the officer’s documented service from the technological origin story he advanced, both of which shaped later disclosure narratives.