Edward James Ruppelt (July 17, 1923 – September 15, 1960) was a United States Air Force officer probably best known for his involvement in Project Blue Book, a formal governmental study of unidentified flying objects (UFOs).

UFO researcher Jerome Clark writes, "Most observers of Blue Book agree that the Ruppelt years comprised the project's golden age, when investigations were most capably directed and conducted.

Shortly after finishing his education, Ruppelt was called back to active military duties after the Korean War began.

In 1956, he worked as a research engineer for Northrop Aircraft Company, according to publisher information in the online version of his 1956 book The Report on Unidentified Flying Objects.

In 1956, Donald Keyhoe asked Ruppelt to join to serve as an adviser to the newly created National Investigations Committee On Aerial Phenomena (NICAP).

In new chapters that were notably conservative in tone, and frequently attributed by reviewers to author disillusionment or disenchantment, Ruppelt declared UFOs a "space age myth".

Content of this nature was of a noticeably different tone to famous quotes from the original "Report" that had, for example, referred critically to a 1949 change of attitude in the Project whereby "everything was being evaluated on the premise UFO's couldn't exist.