A key point of this book is to resolve doubts about the military's role. Ruppelt makes a strong case that UFOs weren't a top secret weapons system; the reports were not disinformation by intelligence agencies; nor was there a concerted effort to cover up UFOs by the US government. Ruppelt does recount many times when the brass tried to dismiss reports without investigating them sufficiently. However, this comes across as simply standard-issue military 'cover-your-ass' behavior, not a vast conspiracy.
He gives unique details on some of the most impressive sightings on his watch. These were largely witnessed by highly trained observers such as radar operators, fighter and commercial pilots, astronomers, and other scientists, often during the course of their official duties. The Air Force group that Ruppelt worked for had access to data on top secret balloon launches and test flights, so they were able to sort out which reports could be explained in this way. He consulted with a wide range of scientific specialists, many of whom were in favor of the extraterrestrial hypothesis, and some who were skeptics.
Fully a quarter of the reports were still unexplained after this rigorous filtering. Ruppelt is decidedly agnostic, but open-minded, about the reality behind the 'unexplained' sightings.