Happy by Derren Brown - not a self help book, more an introduction to classical Greek and Roman philosophy framed around stoicism and a dash of Epicureanism. W

Happy by Derren Brown - not a self help book, more an introduction to classical Greek and Roman philosophy framed around stoicism and a dash of Epicureanism. While it does include mental exercises you can do to aid in a stoic sense of self, I've never found the need to do them, but have definitely become more stoic, and by extension happier, as a result of reading it.