The 2010 book that changed the conversation, subtitled “Generals, Pilots, and Government Officials Go on the Record,” and that’s literally the structure. Kean got firsthand accounts from people with names and ranks: A Belgian air force general, an Iranian fighter pilot, a Peruvian air force officer, the head of France’s space agency, the Japan Airlines captain over Alaska, the military police at Rendlesham air force base. Then the documented incidents — Belgium 1989, Phoenix 1997, O’Hare 2006 — and the history of official evasion. She takes no position on origin and insists throughout on the difference between unexplained and explained. I find her tone toward her sources too solicitous, but facts are facts and these are some mind-bending facts.