Just try Gerald Posner's 'Case Closed'. You'll thank me for it. It's a book that you won't be able to put down and when you're done you'll tell other people that they need to read it whenever the subject of the murder of JFK pops up.
In fact, if you have all of the major conspiracy authors' books (Lifton's 'Best Evidence', Lane's 'Rush To Judgement' and 'Plausible Denial', etc.) in your library, keep them handy for reference while you're reading 'Case Closed'. Posner buries these works so effectively you'll want to find the conspiracist authors and punch them right in their pinko guts and force them to give you your money and wasted hours back.
Perhaps you do?