The Happiness Hypothesis by Jonathan Haidt.

Knowing the person who wrote a book you are reading enriches your experience.  This has not happened to me many times, but having the author’s voice in my head is a great addition. Jon is a psychologist at UVa specializing in the area of positive psychology, which studies how the mind works "well" rather than learning how the mind works based on the its disorders. Most notably, The Happiness Hypothesis is both erudite and readable. Each thought is based on scientific, philosophical, or literary evidence explained in an entertaining and enlightening way. It is written with the aim of helping the reader consider his or her own life and make choices that will allow him or her to be happier.  It is both eminently rational about human behavior and warmly loving about people.