The incomparable Rudy Rucker's just posted an ebook collecting his essays called (what else), Collected Essays. There's a Kindle edition, or you can buy directly from him without DRM. What a table of contents, too:
Collected Essays includes the nonfiction pieces from Rucker's two earlier collections, Transreal! (1991) and Seek! (1999). And many newer essays have been added as well. This comprehensive collection weighs in at twice the length of an ordinary book, with sixty essays and numerous illustrations. The essays fall into seven parts: (1) "The Art of Writing." Manifestos and talks about writing science-fiction. (2) "Silicon Valley." Cool scenes Rucker witnessed as he rode the Silicon Valley computer wave for over twenty years, starting in 1986. (3) "Weird Screens." Graphical programs that have obsessed Rucker—cellular automata, artificial life, fractals, space curves, and virtual reality. (4) "Futurology." Playful raps and speculations about the coming times. (5) "The Philosophy of Computation." Digital immortality, artificial intelligence, and the birth of a universal mind. (6) "Personal Stories." Tall tales and reminscences of strange times. (7) "Mentors." Appreciations of the great minds and wild freaks who led Rucker along his path: Kurt Gödel, Martin Gardner, Robert Scheckley, William Burroughs, Allen Ginsberg, Ivan Stang and Stephen Wolfram.