Hatha Yoga Pradipika
(This is an excerpt from a University Of Metaphysical Sciences course at www.umsonline.org, please feel free to visit the school website)
Now let us turn out attention to hatha yoga. The Hatha Yoga Pradipika was written in Sanskrit by Swami Swatamarama, who was a student of Swami Graknath. English translations can be purchased. This is said to be the oldest text on hatha yoga in existence. It was written in approximately the 15th century AD. Here too, Swatamarama, like Patanjali, is considered a compiler of existing information that was passed down from generation to generation through the teacher student relationship, rather than the author of these concepts.
This book outlines yogic practices, asanas, pranayama, chakras, kundalini, bandhas, kriyas, shakti, nadis, and mudras in detail. This work is too large to include here in this course. However, I encourage you to check this book out if you can and derive what gems you can from it.