Mike O'Mahony

Maybe not 'essential', but pretty good history.

This is not a scholarly work, but it is excellent for my purpose. I want to have a relatively cheap collection of art books with a variety of works to which I can refer when I read about an artist I'm unfamiliar with or a specific painting. This has indexes by both artist and title of work, with a brief discussion of both the artist and the work, as well as related works.

I save the big bucks for favorite artists.