Amazing. I never thought I'd learn Yoga from a book, but it was very helpful. I had trouble with balancing myself for the inverted postures, but was able to have someone else read the form and help me.
Love this book and I am about half way through. It assumes that you know nothing about yoga and starts very simply, breaking down the movements. Each day ends with a short essay about a particular topic that is related to yoga. I have really enjoyed this book. The end has 3 routines that you can continue on with after finishing your 28 days.