The Agony and the Ecstasy

Great book to learn more about not just Michelangelo but also Florence, Rome and all the crazy stuff happening during his life time in Italy.
I highly suggest to use Michelangelo: The Complete Sculpture, Painting, Architecture (https://www.goodreads.com/book/show/7010272-michelangelo) to see the pictures of all the art Michelangelo created - a great companion book.