With so many great science fiction novels available, readers really are spoiled for choice. Some involve artificial intelligence. Others are grand space-operas. And some have even been banned from public distribution for dubious reasons. Every geek has to start somewhere. If you want to build a library of must-have sci-fi novels and novellas, here are the best science fiction books of all time—redefining the genre, gaining cult status, and being adapted for film, television, and radio. 1.