Frauenfelder, Mark; et al., The Happy Mutant Handbook:
Hofstadter, Douglas R.; Dennett, Daniel C. [The Mind's I: Fantasies and Reflections on Self and Soul]: Should be required reading, especially for any AI characters. Short stories and essays on varying subjects with afterwords by D. Hofstadter (author of Godel, Escher, Bach). Topic sections: A Sense of Self, Soul Searching, From Hardware to Software, Mind as Program, Created Selves and Free Will, and The Inner Eye. Mental gymnastics of the highest caliber.
Kaldera, Raven. Schwarzstein, Tannin. The Urban Primitive: Paganism in the Concrete Jungle. 2002. Spends quite a bit telling about how to adapt spirituality, magic, and yourself to a city environment. Might be required reading for those playing Gridshaman characters.
Kurzweil, Ray. The Age of Spiritual Machines: Artificial Intelligence pseudoscience. Covers instantiation, backup minds, nanomachine bodies and post-corporeal love.
Lilly, John C. Metaprogramming the Human Biocomputer:
McKenna, Terrence. The Archaic Revival: Fiction and non-fiction are just marketing schemes. Remember that -;)
Rushkoff, Douglas. Cyberia: Life in the Trenches of Cyberspace. 1994. Drugs, fractals, Internet and usenet in particular, spirituality, sexuality, psychology, philosophy, and other highly relevant things. http://www.rushkoff.com/cyberia.html
Stang, Ivan; et al., The Book of the Subgenius:
Sirius, R. U. How to Mutate and Take Over the World: