I am a sucker for a great reference book especially if it has a science, history or philosophy focus.
The following is a list of twenty reference books that I read and peruse through on a regular basis.
1. The Timetable of World History - Bernard Grun
2. Atlas of WorldHistory - John Haywood - One of my top ten buys ever.
3. Chronicle of the 20th century - Longman - Top 10 buy
4. Holocaust Chronicles - Publication International Limited
5. Encyclopedia of Science and Technology - James Trefil
6. The New York Public Library Science Desk Reference
7. 100 Most Influential Books Ever Written by Martin Seymour-Smith
8. Larousse Dictionary of World History - Top 10 Buy
9. A Dictionary of Modern History by A. W. Palmer - Another Top ten buy
10. The Timetables of Jewish History by Judah Gribetz and Edward Greenspan
11. 1000 Great Lives - Plantagenet Somerset Fry
12. 1000 Great Events - Plantagenet Somerset Fry
13. Timelines of war - David Brownstone and Irene Franck
14. Encyclopedia of Mystical and Paranormal Experience by Rosemary Ellen Guiley
15. Whos who in the Old Testament - Joan Comey
16. The Dictionary of Science Fiction Places - Brian Stableford
17. Secret Societies - David Barrett
18. A History of the Sciences - Stephen Mason
19. The Penguin Dictionary of Astronomy by Ake Wallenquist
20. Dictionary of British History - J.P. Kenyon
Check them out on the internet if they are still in print I recommend acquiring one or two of the above.