One of the best Francis Bacon art books (and best art books in general) is https://www.amazon.com/Camera-Francis-Photography-Practice-P...

It juxtaposes the source material Bacon used for his paintings (pictures, film, other painting mostly by Velazquez etc.) with the eventual paintings.

This is briefly mentioned in the New Yorker article but a fascinating aspect of his work: he was remixing / paraphrasing all the time!