As far as I can tell, Munger is the one who really popularized the notion of mental models, so this is a must-read.

For anyone not in the know, Munger is Warren Buffett's business partner. The basic idea is to collect an interdisciplinary checklist of different paradigms for viewing the world, and then run through that checklist and apply each mode of thinking to whatever tough problem you're working through.

HN readers probably already know all of this, but I just love this approach to thinking and wanted to share the wealth :)