Here's some good ones...
1, Accessories After the Fact by Sylvia Meagher (a smart lady looks at the facts)
2. Six Seconds in Dallas by Josiah Thompson (a brilliant philosophy professor re-examines the forensic evidence. Note while I disagree with many of my friend Tink's findings, there's no disputing he set a high bar.)
3. Post Mortem by Harold Weisberg (an almost Fellini-esque character study/rant revolving around a crotchety old man's efforts to make his government transparent and accountable.)
4. The Last Investigation by Gaeton Fonzi (a gripping detective story in which a journalist tries to get to the bottom of the murder of the century)
5. Someone Would Have Talked by Larry Hancock (the culmination of a hard-working man's efforts to separate the facts from the fiction, to see what remains).
There are, of course, a number of others which have something to offer.
I wish there was a good Oswald-did-it book which I could recommend. The problem, for me, is that almost all of them embrace the single-bullet theory as a fact, which, to me, is absolute rubbish. So I could no more recommend a book pushing this rubbish than I could a book pushing that Onassis did it so he could hook up with Jackie, or one in which a teenage hit man fired the fatal shot.
It is with high hopes then that I look to Robert Wagner's next book.