The former head of the Pentagon program responsible for the investigation of UFOs—now known as unidentified anomalous phenomena (UAP)—reveals long-hidden secrets with profound implications for not only national security but our understanding of the universe. For years, Elizondo and his colleagues found themselves on the front lines of what may be the greatest mystery and cover-up in history. Unidentified craft that seem to defy our knowledge of physics—within air, water, and space—have been operating with complete impunity since at least World War II. The military, the CIA, and even past presidents have known the truth that humanity is, in fact, not the only intelligent life in the universe. The nonhuman intelligence controlling these UAP are actively conducting surveillance on our most sensitive military installations, and have interfered with ongoing military and nuclear operations. US service members and intelligence officers who have encountered UAP have sustained serious medical injuries. And all of this is happening worldwide. The stakes could not be higher. Imminent is a first-hand, revelatory account inside the Pentagon’s most closely guarded secret and a call to action to confront humanity’s greatest existential questions.