Satyananda Yoga Nidra is a simple yet profound technique adapted by swmai satyananda Saraswati from the traditional tantric practice of nyasa. This text explains the theory of yoga Nidra in both yogic and scientific terms and includes Class transcriptions of the practice. It also presents the various applications of this versatile technique, which has been used for deep relaxation, in stress management and therapy, to enhance the learning process in education, to harmonize the deeper unconscious and awaken inner potential, and as a meditative techniques. A research section is also included.