I just wanted to know where yoga we practice today came from, I mean I would like to know who actually told us all to practice the asanas the way we practice them today. The book covers lots of things, Tantra and yoga and Buddhism, this is good enough for me, and it does read like a text book, not a light read, rather an investigation... I just want a broad view on yoga's roots, and I guess it's a good thing that the book is not written by just one author. The book is a collection of works by different authors.