suggested reading:

Hatha Yoga Pradipika by Swami Muktibodhananda

The Bhagavad Gita translated by Eknath Easwaran

Yoga Mala by Sri K Pattabhi Jois

Roots of Yoga by James Mallinson

Yoga Sutras of Patanjali by Edwin Bryant

The Yoga Sutras of Patanjali translation by Sri Swami Satchidananda

Guruji: A Portrait of Sri K. Pattabhi Jois Through the Eyes of His Students

Ashtanga Yoga Anushtana by R. Sharath Jois