I grew up reading the Time-Life series of books on famous authors, which in my memory from way back, seemed to explain a lot.
You might want to go to a college bookstore and see what books they are using for their art appreciation course as well.
I do recommend, if you don't have them yet, a copy of Bulfinch's Mythology, including the Age of Fable, because that's a great place to look up a lot of the background stories from myth and legend.
I'm an art and literary junkie, but not up to date on who's good for art reference. But literary reference, come and ask!
Bulfinch's Mythology was one of my favorite books growing up. It and Grimm's Fairy Tales :)