...the path of physical transformation

Hatha or haṭhayoga is the physical techniques/postures called asana, which supplements the broader conception of Yoga as a whole. It includes Yogic practices involving purification of the body such as:Hatha-Yoga-Pradipika



Another definition of what hatha practice is and includes:

Western perspective on hatha Yoga.

Books, CDs, etc.

A traditional Yoga text briefly explaining hatha yoga.