My search for JFK assassination material began when I booked a trip to Dallas for a football game. I really didn't have any preconceived notions on whether the assassination was a conspiracy or not. I simply wanted to educate myself on what I would be looking at when I visited the Dallas School Book Depository. After reviewing most of the well known theories on wikipedia.com, I decided to purchase a book that went into depth on why Oswald acted along.
"Case Closed" does a good job giving the reader an insight on what Lee Harvey Oswald was all about. It also goes in depth on the background of Jack Ruby. Most impressively, Posner does a fantastic job citing where and how his information was obtained.
When I finally got the the sixth floor of the Depository, I quickly came to the conclusion that the shot from the window was not a difficult shot to make (esp in 3 attempts). I also made a point to go down to the grassy knoll. I couldn't help but think to myself, "the grassy knoll sure is close to location where the president was shot. If the shots came from there how could not everyone notice?"
What sealed the deal for me was watching the assassination on youtube.com. One can clearly see that when the second shot is fired, both the President and Governor react as if they have been hit at the same time. You have to ask yourself, if it wasn't a "single bullet" that hit them both, what is the probability that a conspirator(s) could make it appear as if it were a single shot?
In my opinion, if Jack Ruby hadn't shot Oswald, there would be no conspiracies.