 The Riddle of Scheherazade by Raymond Smullyan |  To Mock a Mockingbird by Raymond Smullyan |  Forever Undecided by Raymond Smullyan |  The Lady or the Tiger? And Other Logic Puzzles Including a Mathematical Novel That Features Godel's Great Discovery by Raymond Smullyan |  The Moscow Puzzles by Boris A. Kordemsky |  The Colossal Book of Short Puzzles and Problems by Martin Gardner |  On Formally Undecidable Propositions of Principia Mathematica and Related Systems by Kurt Godel |  My Best Mathematical & Logic Puzzles by Martin Gardner |  What is the Name of this Book? by Raymond Smullyan |  Alice in Puzzle-Land by Raymond Smullyan |  The Unexpected Hanging and Other Mathematical Diversions by Martin Gardner |  Aha! Gotcha by Martin Gardner |  Mathematical Circus by Martin Gardner |  Mathematical Carnival by Martin Gardner |  The Second Scientific American Book of Mathematical Puzzles and Diversions by Martin Gardner |  The Elegant Universe by Brian Greene |  Pale Blue Dot by Carl Sagan |  Hyperspace by Michio Kaku |  The Seven Mysteries of Life by Guy Murchie |  A Universe from Nothing by Lawrence M. Krauss |