Give me a list of science fiction books that every sci-fi fan should read.
The following books are strongly recommended for any science fiction fan to read:
 - The Three Body Problem Trilogy by Cixin Liu
 - Dune by Frank Herbert
 - The Robot Series by Isaac Asimov
 - Foundation Trilogy by Isaac Asimov
 - Ender's Game by Orson Scott Card
 - A Hitchhiker's Guide to the Galaxy by Douglas Adams
 - The Stand by Stephen King
 - The Children of Men by PD James