A small book that packs a punch. Different context, but the psychological principles for the player are on point.
Books on trading psychology mostly deals with self-discipline. No doubt, this is very important. However, in order to become a successful trader, you need another psychology, and that's called "market psychology". Whereas trading psychology is mostly about yourself, market psychology is about how the market participants react to the flow of money, eg. greed and fear.
An unconventional pick but having read this one, I'd agree with you 100%. Few will take you up on it, however.