John Michael Callahan is the author of Lethal Force and the Objectively Reasonable Officer published by Looseleaf Law Publications in August. The book is an extensive guide to lethal force case law, training methods, and officer survival tips. During his forty-four years in law enforcement, thirty of them in the FBI, Callahan was chief division counsel in two FBI field offices and taught Constitutional Criminal Procedure at the FBI Academy in Quantico, VA.