1. Catch-22, Joseph Heller - Funniest and most tragic book I ever read.
2. Farenheit 451, Ray Bradbury - Best social responsibility theme
3. Ender's Game, Orson Scott Card - The stupidity of war
4. Rebecca, Daphne du Maurier - Understanding the value of oneself
5. To Kill A Mockingbird, Harper Lee - Understanding bigotry in the South
6. 1984, George Orwell - The futility of political power and social slavery
7. Great Expectations, Charles Dickens - Lost love and growing up
8. The Old Man & The Sea, Ernest Hemingway - Courage, defeat, and winning.
9. The Hitchhiker's Guide to the Galaxy, Douglas Adams - Life, the Universe, and EVERYTING!
10. The Source, James Michener - Explains the "holy land" and how religion became a "thing". Plus it's a great explanation of archeology and paleoanthropology.