I've been seeing references to Vannevar Bush's 1945 essay about what would become hypertext, As We May Think. It's nice to see it popping up again, and since I was heavily influenced by it while in high school but haven't read it since, it's back on my reading list.

Another big influence and great source of ideas was Ted Nelson's Literary Machines, which, after being hard to find for a long time, is apparently back in print. Much of the book is now online as scanned images, but it uses "jfax" format, which seems a bit counterintuitive, but oh well.