From the longer Wikipedia page 
The book is divided into two major parts, with a prologue, an epilogue and two appendices.
- The prologue describes the situation before Richard's birth, leading up to the Wars of the Roses.
- The first major part deals with Richard's early life as son of Richard, Duke of York and brother to Edward IV. It deals covers Richard's youth and his life as Duke of Gloucester (13 chapters) as well as his role as "Lord of the North" (6 chapters).
- The second part covers Richard's life after the death of Edward IV in 1483, first as Lord Protector (8 chapters), then as King (12 chapters).
- The epilogue describes the situation after Richard's death at Bosworth, especially the farings of his associates under Henry VII.
- Appendix I deals with the question of the Princes in the Tower, weighing the evidence about their fate. He criticizes traditionalists for ignoring the "disablities inherent in the 'evidence'" and revisionists for having "put forward a melange of wishful thinking and speculation". Examining the evidence and commenting on several indications of Richard's innocence, he concludes:
"The most powerful indictment of Richard is the plain and massive fact that the princes disappeared from view after he assumed the throne, and were never reported to have been seen alive. This fact ... weighs heavily against the indications of his innocence.Considering alternative culprits, Kendall discounts claims that Richard's successor Henry VII could have killed the princes after 1485, but makes a case for Richard's temporary ally, the Duke of Buckingham, who could have killed the princes with or without Richard's knowledge and consent.
... only positive evidence that someone murdered the princes will tell against this indictment."
- Appendix II deals with Richard's posthumous reputation.