Recommend some books on photography (as an art form).

After visiting the International Center of Photography, the Diane Arbus exhibit at the Met and MoMA’s photography wing last week, I’m newly curious about the history of photography as an art form. I’m familiar with many of the big names (and even some of the not-so-big names), but I don’t have a good sense of how it all fits together, who influenced whom, etc.

Can anyone recommend some good books on the history of photography – emphasizing the art, rather than the technical aspects? (Not that those aren’t interesting, but I want to know more about the works and creators than the equipment.)