Written from the unique perspective of a professional shooter, "Kill Zone: A Sniper Looks at Dealey Plaza," not only demolishes all the arguments of lone-assassin proponents, but examines the myriad reasons why Kennedy was killed. The reason I knew that Oswald could not have done it, was because I could not have done it, said former US Marine sniper, Craig Roberts. Credited with numerous kills while serving in Vietnam , Roberts turned an objective eye on the shot heard ‘round the world. After he visited Dealey Plaza, after viewing the so-called sniper’s lair, on the sixth floor of the book depository, and after staring at the large oak tree overspreading much of Elm Street, Roberts said, I walked away from the window in disgust. I had seen all I needed to know that Oswald could not have been the lone shooter. But Roberts, a retired police investigator, wanted to know what did happen. Not content to dismiss the improbable feat, he delved into the crime from every angle. First, I analyzed the scene as a sniper . . . I looked at the engagement angles. It was entirely wrong. Here, from what I could see, three problems arose that would influence my shots. First, the target was moving away at a drastic angle to the right from the window, meaning that I would have to position my body to compete with the wall and a set of vertical water pipes . . . This would be extremely difficult for a right-handed shooter. Second, I would have to be ready to fire exactly when the target emerged past some tree branches that obscured the kill zone. Finally, I would have to deal with two factors at the same time; the curve of the street, and the high-to-low angle formula, a law of physics Oswald would not have known. Not content with his own critical appraisal, Roberts turned to another, equally knowledgeable shooter. According to my friend, Gunnery Sergeant Carlos Hathcock, the former senior instructor for the US Marine Corps Sniper Instructor School at Quantico, Virginia, it could not be done as described by the FBI investigators. Let me tell you what we did at Quantico, Hathcock recalls. We reconstructed the whole thing: the angle, the range, the moving target, the time limit, the obstacles, everything. I don’t know how many times we tried it, but we couldn’t duplicate what the Warren Commission said Oswald did. Now if I can’t do it, how in the world could a guy who was a non-qual on the rifle range and later only qualified 'marksman' do it? Of course, sergeant Carlos Hathcock was only the most famous American military sniper in history, credited with a confirmed 93 kills. But apologists for a lone assassin, who continue to enjoy mainstream media sponsorship 40 years later, continue to argue that an average shooter like Oswald, using a decrepit, war surplus weapon, could have killed Kennedy. Case closed.