Six universal principles of persuasion: reciprocity, commitment, social proof, authority, liking, and scarcity. Ostensibly about marketing, but the implications for investing are enormous. Every bubble is social proof in action. Every pump-and-dump exploits authority and scarcity. Munger considers it essential reading for understanding why markets behave the way they do.

The case for it, the case against, and the rest of the canon open with Pro.