Don Miguel Ruiz

A Mexican surgeon who had a near-fatal car accident, left medicine, and turned to the Toltec tradition his family had practised for generations.

The Four Agreements sets out four rules: be impeccable with your word, take nothing personally, make no assumptions, and always do your best. The second and third do most of the work, and the book is short enough to read in an evening.

It has sold in the millions and is presented as ancient wisdom, though how directly it maps onto historical Toltec practice is contested by scholars.