Books ABOUT hypertext etc.

This thread is for discussions of hypertext/new media theory and scholarship. I, for one, would especially like to hear what others think are important recent books in this field. Back in the late 90s, when I was studying for my orals, I read alot of the "first-generation" hypertext theorists: Landow, Bolter, Michael Joyce, Aarseth, and of course Theodor Nelson, but since then I have not been especially good about keeping up.