Future Imperfect describes and discusses a variety of technological revolutions that might happen over the next few decades, their implications, and how to deal with them. Topics range from encryption and surveillance through biotechnology and nanotechnology to life extension, mind drugs, virtual reality, and artificial intelligence. One theme of the book is that the future is radically uncertain. Technological changes already begun could lead to more or less privacy than we have ever known, freedom or slavery, effective immortality or the elimination of our species, and radical changes in life, marriage, law, medicine, work, and play. We do not know which future will arrive, but it is unlikely to be much like the past. It is worth starting to think about it now.