Probably the best book debunking all the conspiracy theories is "Case Closed", by Gerald Posner.
He does an exhaustive investigation of all the theories and shoots them full of holes.
This is easy, since MOST of them are stupid at best.
Jim Garrison was a sleazy New Orleans politician who played fast and loose with facts and the truth long before he set out to make a name for himself on JFK's dead body.
He also lists the "Mysterious deaths of 100 people involved in the Kennedy conspiracy".
These 100 people who died under "mysterious" circumstances are often referenced to "prove" there was a cover up.
The list is hilarious in places.
It lists an assistant New Orleans Medical examiner, 100 pounds overweight, who smoked 4 packs of cigarettes a day, drank like a fish, and ate high-fat foods like a pig.
He "mysteriously" dropped dead of a heart attack.
He, by the way had nothing to do with the case, he was simply employed at the office.
Another was a BROTHER to some minor figure who himself had nothing to do with anything, but who was just around.
Bottom line is, all the REAL evidence points to Oswald as the sole and only shooter, and there is NO valid evidence indicating anyone else.
Much of the conspiracy theories have been overtaken by events and science.
As an example, the recent program referenced above, PROVED there was no "shooter on the grassy knoll".
The apparent shadow HAD to be one of two things, IF IT WAS A PERSON.
1. It was a person about 30 inches tall. This was indicated by a size comparison between the shadow and a real person. The shadow was WAY too small.
2. If it was a person, in order for the size to match, he would have had to be 60 yards BEHIND the knoll, AND 20 to 30 feet up in the air.
Now, no one ever reported a Tom Thumb-sized shooter, and 60 yards back would have put the shooter in the train yard standing on a cherry picker.
What all this boils down to is known as "The Great Man Syndrome".
The Great Man walks out of his palace, prepares to step into his limo, steps on a banana peel, slips falls, and breaks his neck.
That however is NOT possible. He's a Great Man, and Great Men DO NOT die common deaths like everyone else.
It HAD to be a vast conspiracy.
The banana peel was PLANTED, (after being greased).
The body guard tripped him.
He was really shot with a disintegrating poison dart.
It really wasn't him it was an impostor.
Etc.
This is why Marylin Monroe was murdered, Jessie James actually died in Texas years later, (or was it New Mexico?, Billy the Kid died an old man in Mexico, John Dillinger faked his death, the embarrassed FBI covered it up, and Dillinger wound up working in California aircraft plants until he retired.
