The popular classical text Hatha Yoga Pradipika has been translated into English and presented in its full form without editing/omitting any phrase or verse from the original Sanskrit text. It is seen that some of the authors/translators of Hatha Yoga Pradipika and some classical texts on yoga and tantra have not included the original Sanskrit verses on Vajroli, Amaroli and Sahajoli mudras in their books which are the practices of (tantric) sexual acts. They have considered that these mudras fall in the category of 'impure sadhana (practice)' and they are practiced by 'low-class tantrists'. It was felt fair and necessary to include all the verses from the original text of Hatha Yoga Pradipika on the mudras and other practices and to translate them completely. Therefore, each of the Sanskrit verse of this popular text with its 'as it is' translation has been presented in this book. A sincere effort has been made in order to present the translation of this renowned classical text as simple and understandable as possible. Hatha Yoga is known as the science of purification. It is believed that total purification of all impurities on the physical level is absolutely necessary in order to purify the mind. When these impurities are eliminated from the body, the energy blocks are removed and Nadis (the subtle channels in the pranic body) function properly. Then the Prana moves freely throughout these subtle channels within the total physical structure. Therefore, it is considered that various aspects of the practice of Hatha Yoga e.g. asana, pranayama, mudra, bandha and shatkarma serve as the solid foundation for the preparation and practice of Raja Yoga, Kundalini Yoga, Kriya Yoga and Tantra. Originally, the science of Hatha Yoga was not discovered for yoga therapy, but for the expansion and evolution of human consciousness. Although yoga has been scientifically proven to be effective in the treatment of many incurable diseases, the therapeutic effect of yoga is only a byproduct.