I thoroughly enjoyed listening to the audio version of The Happiness Project by Gretchen Rubin. Like books by Gary Vaynerchuk, it was read by the author, which added richness to the experience.
There were a lot of good examples in each chapter of behaviors the author tried, and I liked her overall objective of learning about and experimenting with happiness within the context of her current life situation. It was exactly the blend of psychology and philosophy that I enjoy. I especially enjoyed her use of quotes that inspired her and scientific studies that backed up some of the practices she tried. (There were also several points in the book when she sounded like one of my MBA profs -- perhaps she also got an MBA at some point or just read a lot of business books!)
Overall, through her journey in the book, the author came to learn "Four Splendid Truths" about happiness:
Four Splendid Truths
It was also neat to hear about her own "Personal Commandments" and "Secrets of Adulthood" -- a lot of these (and the splendid truths) resonate with me.
Twelve Personal Commandments
Secrets of Adulthood
Ch. 12: December