Much like the first Science of Discworld book it combines two of my favorite things, the silliness of a Terry Pratchett story with hard science. The book is set up so each chapter alternates between a Discworld story and then a detailed discussion of some science that was involved in the story. Topics cover, evolution, quantum physics, speed of light, multiverses, and memetics to name a few. Great fun for any science geek that enjoys Terry Pratchett's books.