Yoga should be taught by a teacher but if you're looking for a more intellectual, philosophical read, then this one is for you.
Aleister Crowley's work is largely a demystified look at yoga, using little to no jargon or satirical humor. Sounds boring, but it really is quite fascinating. He instructs students on the steps to approach mysticism through Yoga, and details the complications that arise along the path. What Crowley really wanted to do was to dispel the various myths surrounding Yoga in Europe at the time. So this book really, covers, in detail, the philosophical, mathematical, and scientific aspects of yoga. Perfect for the ones who are obsessed with detail and form.