Robert Orel Dean (1929–2018), known as Bob Dean, was a retired U.S. Army noncommissioned officer from Tucson, Arizona, who became one of the best-known speakers on the UFO lecture circuit from the early 1990s. His central claim was that while serving at Supreme Headquarters Allied Powers Europe (SHAPE), NATO's military headquarters in Europe, he read a highly classified study he called "The Assessment," which he said concluded that Earth was being visited by extraterrestrials who posed no military threat.

Dean retired from the Army in 1976 after more than 27 years of service, and press accounts give his final rank as command sergeant major. SHAPE personnel rosters show a Sergeant First Class Robert O. Dean assigned to the headquarters from the summer of 1963 to the spring of 1967, first in the Operations Division and later as chief clerk of a language services branch, according to SHAPE historian Gregory Pedlow. After leaving the Army Dean worked for Pima County Emergency Services for 14 years. When Sheriff Clarence Dupnik passed him over for promotion, citing his belief in UFOs, Dean sued, and in March 1992 the county settled the case for $100,000 in damages. He said that afterward he "literally came out of the closet on this issue."

Dean told his story in lectures and in outlets ranging from Omni magazine to CNN's Larry King Live. He said the Assessment was a roughly three-year inquiry begun after unidentified objects were tracked flying over Europe, and that only 15 copies were produced. He expanded the account into a wider story of a multi-agency cover-up and of visits by several extraterrestrial civilizations, one of which, he said, looked so human that its members could walk through NATO headquarters unnoticed.

Pedlow's report, The Alleged SHAPE "Assessment" of UFOs in 1964: What the Official Records Show, sets out what NATO's archives contain. Searches beginning in 1991 of SHAPE's records, including classified microfilm, of NATO headquarters staffs and of intelligence files found no trace of such a study. A photograph of the supposed cover sheet supplied in 1993 by the British researcher Timothy Good carried a "NATO COSMIC TOP SECRET" marking that never existed and the British wartime codeword ULTRA, and Pedlow judged it and a purported clearance document to be forgeries. He confirmed that Dean served at SHAPE and would have held a COSMIC TOP SECRET clearance, but concluded that "no such document was ever produced by SHAPE or NATO."

Dean passed away in 2018, and clips of his talks circulated again in 2026. In May the InterstellarUAP account posted his statement that Earth had been visited by "at least four different extraterrestrial civilizations." In October the researcher Joe Murgia cited a 1998 Coast to Coast AM interview in which Dean recounted Robert Bigelow saying there was "only one agenda." Dean's account endures as one of ufology's most repeated insider stories and one of the few that an institution answered directly from its own archives.