Josephine Tey convinced me (years ago) that Richard III was maligned and innocent. Since then I've discovered that not everyone agrees with her logic.
The Year of Three Kings, 1483 was published in 1983,and written by Giles St Aubyn, one of those who weren't as convinced. It is my last intensive teacher-read before the school year starts; I'm about halfway through, and I'm finding it good straightforward history--though not as easy to get through as Tey's fictional approach.
(Funny what things come back to you. As soon as I read the name Lovell, I remembered the rhyme from Daughter of Time about "The Cat, the Rat, and Lovell our dog," and I was pretty pleased with myself for getting that right when Catesby and Ratcliffe turned up a few pages later.)
