Richard III: A Ruler and His Reputation
The unavoidable twin poles of King Richard III are William Shakespeare and Josephine Tey. Shakespeare casts him as a kind of medieval Grand Moff Tarkin, monstrous and subtle and without any redeeming features. Tey, in her classic detective story The Daughter of Time, pictures him as the victim of a merciless posthumous image-blackening campaign, chiefly by his successors on the throne.
David Horspool's book is a reasoned attempt to navigate between them. It's neither excessively condemnatory nor fawningly exculpatory. I wouldn't call it a riveting read, but it's decent and thorough. It does assume that the reader is already familiar with the subject matter; it spends a lot of its page count supporting or debunking various claims by various factions, which is not likely to interest you if you hadn't heard the claims in the first place.
Also, the period of the Wars of the Roses is a hard one to render into narrative. There are too many betrayals, too many families, and too many characters. The same few first names, surnames, titles, and offices recur in dizzying combinations. I've read worse. Indeed, I've read much worse. But it would take a master storyteller to keep track of them all, and David Horspool is not that man. His failure to include a Who's Who is regrettable; the lack of maps is inexplicable; but the absence of any family trees is criminal. Good luck keeping the players sorted out without them.
So: eh. Richard III the book is judicious, scholarly, readable, and mainly aimed at those who are substantially interested in Richard III the person. If that's you, go ahead and read it. If not, start somewhere else.
Do read The Daughter of Time if you haven't already done so. Do remember that it's a story and not a scholarly tract, though.