Imminent: Inside the Pentagon's Hunt for UFOs is the memoir of Luis Elizondo, the former Army counterintelligence officer who says he ran the Pentagon's Advanced Aerospace Threat Identification Program before resigning in 2017 to take the subject public. William Morrow, an imprint of HarperCollins, published it on August 20, 2024, and it debuted at number one on The New York Times best-seller list. The book follows Elizondo from counterintelligence work to the Office of the Under Secretary of Defense for Intelligence and through his campaign for congressional attention after he left.

Elizondo writes that he was recruited late in his career to manage security and counterintelligence for a classified UFO research effort, and that a crash-retrieval program has run in secret for decades through an umbrella group of officials and defense contractors holding technology and biological remains he says are not human. He also describes glowing orbs he says visited his family's home for years and his part in a remote-viewing effort under the physicist Hal Puthoff. An Associated Press review noted that several passages are redacted and that Elizondo says he cannot say more on some subjects; it found the book thorough but crowded with government acronyms.

The Defense Department has disputed both his role and his central claims. A Pentagon spokesman said in 2019 that Elizondo "had no responsibilities with regard to the AATIP program" while at the intelligence office, although former Senate leader Harry Reid wrote that he had held a leadership role in it. After Elizondo testified to Congress in November 2024, the department said it had found no verifiable evidence of extraterrestrial activity or of any program possessing or reverse-engineering extraterrestrial materials. The economist Tyler Cowen valued the book's account of how the bureaucracy handled UAP reports but said he could not recommend it because of "apparent blatant falsehoods."

The memoir remained a reference text in the 2026 disclosure debate. In August, as Elizondo answered allegations about James Clapper raised in a public dispute with UAP Gerb and Ross Coulthart, a critic on X circulated the book's photo caption showing Elizondo with Clapper, his "old boss," at CNN the day after the December 2017 New York Times story. In September, Reddit readers cited its account of an underwater object said to have swallowed a missile during a military test after UAP Gerb said he believed in an underwater facility. Two years after publication, it was still the fullest statement of Elizondo's case and the text both his supporters and his critics quoted.