Last Second in Dallas is not a conspiracy book. No theory of who did it is offered or discussed. Among the discoveries: The test showing that all recovered bullet fragments came from Oswald's rifle was mistaken. Several fragments could have come from bullets of any manufacturer and any caliber. The sudden two-inch forward movement of the president's head in the Zapruder film just before his head explodes is revealed to be an optical illusion caused by the movement of Zapruder's camera. This leaves without further challenge clear evidence that this shot came from a specific location to the right front of the limousine. Detailed analysis of film frames matched by the newly validated acoustic evidence show a second shot struck the president's head from behind less than a second later. Result: two killing shots to the head from opposite directions in the final second of the shooting--hence the book's title.

At once a historical detective story and a deeply personal narrative by a major figure in the field, Last Second in Dallas captures the drama and sweep of events, detailing government missteps and political bias as well as the junk science, hubris, and controversy that have dogged the investigation from the beginning. Into this account Thompson weaves his own eventful journey, that of a Yale-educated scholar who in 1976 resigned his tenured professorship in philosophy to become a private investigator in San Francisco, developing a national reputation.

Profusely illustrated, Last Second in Dallas features dozens of archive photographs, including Zapruder film frames reproduced at the highest clarity ever published.