Well before we understand how brains work, we may find ourselves able to digitally copy the brain's structure and able to download the conscious mind into a computer. What are the possibilities and challenges?
SUM was chosen as the best book of 2009 by Chicago Tribune's Pulitzer-winning literary critic Julia Keller.
Hear the actress Emily Blunt (Young Victoria, Devil Wears Prada) read "The Cast" from Sum. She is one of the dozens of terrific actors who read for the audio book.
Read David's new article in Wired magazine: "Apocalyse? No. Six Ways the Internet Will Save Civilization"