OK, so far I have gleaned these from searching the forum archives:
economic crash books
Crash Course by Chris Martenson
Game Over: How You Can Prosper in a Shattered Economy by Stephen Leeb
The Coming Economic Collapse: How You Can Thrive When Oil Costs $200 a Barrel by Stephen Leeb and Glen Strathy
Endgame: The End of the Debt Supercycle and How It Changes Everything - Hardcover by John Mauldin and Jonathan Tepper
permanent portfolio
http://harrybrowne.org/
Fail-Safe Investing: Lifelong Financial Security in 30 Minutes by Harry Browne (Jan 10, 2001)
How You Can Profit From the Coming Devaluation by Harry Browne
You Can Profit from a Monetary Crisis by Harry Browne
Inflation-Proofing Your Investments: A Permanent Program That Will Protect You Against Inflation and Depression by Harry Browne and Terry Coxon (Dec 1981)
http://www.gyroscopicinvesting.com/forum/
What else?