INDEX (work in progress)
Agriculture/Food
Architecture/City Planning
Astronomy/Planet-Building
Earth: Evolution of a Habitable World by Jonathan Lunine - Generously illustrated, and touches on many different sciences in explaining the earth's evolution.
What If the Moon Didn't Exist?: Voyages to Earths That Might Have Been, by Neil F. Comins - An accessible look at alternate-earth scenarios based on hard science.
Biology/Creature-Building
Survival of the Sickest: A Medical Maverick Discovers Why We Need Disease, by Dr. Sharon Moalem with Jonathan Prince - A look into why genetic diseases exist, and how they actually stem from beneficial mutations.
Clothing/Costume
Culture/Psych/Social
The Archetypes and The Collective Unconscious, by Carl Jung - Classic psychological work explaining recurring themes and roles that have existed in human society throughout history. Important for all storytellers!
Geography/Map-building
History
The Mediterranean and the Mediterranean World in the Age of Philip II, by Fernand Braudel - Explores the culture of the Mediterranean in the late 16th century in a panoramic way that focuses more on principles than events.
Four Thousand Years Ago: A World Panorama of Life in the Second Millennium BC, by Geoffrey Bibby - A slightly dated but still-beloved text that fires the imagination by bringing various scenes from the Bronze Age world to vivid life.
Linguistics/Languages
Politics/Government
Origins of the State and Civilization by Elman R. Service - How forms of government develop hand-in-hand with technology/civilization.
Religion/Spirituality/Myth
Elementary Forms of the Religious Life, by Emile Durkheim - Explores the universal human tendency toward ritual, magic, and myth.
Ships & Sailing
SHIP, by Brian Lavery - Comprehensive visual introduction, covers from the very first floating vessels to the present day. Maps and photos galore!
War & Weaponry
Multiple Subjects
Guns, Germs, and Steel, by Jared Diamond - Pulitzer winner that covers the development of society from its very beginnings and explores why some societies/cultures dominate others.
The 10,000 Year Explosion, by Gregory Cochran - A concise look at the material/evolutionary benefits of civilization. Excellent when combined with a study of Diamond's book.
World Builder's Guidebook, D & D 2nd Edition - great for spur-of-the-moment "Oh crap I need detail NOW!" reference.