Yoga nidra is a meditation technique that is part of the tantric tradition. In the ancient texts or Tantra Shastras it is known as nyasa, a complex and time-consuming procedure involving knowledge of mantras, chakras and the Sanskrit alphabet. Swami Satyananda Saraswati discovered this technique while revising these texts. Recognizing the need for such a practice in the modern world, he devised a simple and effective form of yoga nidra suitable for everyday use and commenced using this in 1962. The present practices have evolved from this time.

This compilation is from lectures and classes on yoga nidra that Swamiji has given in the last eight years. It is divided into two sections, theory and practice. Complete practices are presented along with additional material that allows the reader to develop many more. These are representative of practices given by Swamiji as well as of practices given by swamis from the Bihar School of Yoga. A determined effort has been made to present the practices in as clear and simple a fashion as possible so that all who use them will be able to obtain maximum benefit.

Yoga nidra is a systematic method for inducing complete physical, mental and emotional relaxation. Yoga nidra is composed of two Sanskrit words, yoga meaning 'union' or one-pointedness, and nidra, which in its corrupt form means 'sleep', but is more correctly understood as relaxation. Thus yoga nidra means relaxation by creating one-pointedness of mind.

Yoga nidra can be used as a preliminary to sleep or as an alternative to it. Many people go to sleep in the act of reading or thinking over some problem or prey to some anxiety. In sleep their mind runs on with the same thoughts and worries and their body remains tense. When they wake up in the morning they still feel tired and lethargic and find it difficult to get out of bed. For some time before rising they dose between dreaming and wakefulness. For the average healthy person, eight hours of sleep it quite enough.

If yoga nidra is practiced just before sleeping the whole body and mind are relaxed, sleep is deep and refreshing, and less sleep is needed. Yoga nidra should also be practiced at other times of the day, so as to gain its benefits as a meditation technique. When practiced successfully in this manner it also produces a feeling of complete refreshment. One hour of yoga nidra during the day is equal to four hours of sleep at night.

Yoga nidra is a method of pratyahara or sense withdrawal which markedly reduces the awareness of the outside world and the physical body. This is accomplished by systematically rotating the mind through the different parts of the body. In a similar way the awareness is rotated through various thoughts and feelings, causing withdrawal from these. In the deep state of relaxation that resides, many, tensions are released and the mind is cleansed of disturbing material. The mind becomes clear and we are able to contact our inner personality. In yoga nidra positive suggestions made to oneself have a very powerful effect and can change one's whole life. Use of this is made by formally including an opportunity to make a resolve at the beginning and end of the practice. A state of heightened receptivity is induced that is excellent for learning, because material is dropped directly into the unconscious mind without the interference of the conscious mind. The major advantage of this in yoga nidra is that the whole method is learned quickly and thoroughly by the student so that he is soon able to practice it by himself, without the help of a teacher. It also offers great potential, as yet largely unexplored, in the field of education. For example, experiments conducted in Bulgaria have indicated that by using a similar method to yoga nidra, foreign languages that formerly took two or three years to learn can be mastered in a matter of a few weeks.

The practice of yoga nidra can turn your life into an expression of well-being and joy. Those people who know how to relax can work more efficiently, enjoy life more fully and have better relations with other people. Whereas tension leads to dissipation of energy and attention in all directions, true relaxation allows us to recuperate mental and physical power and to focus it in one direction when required. In this way yoga nidra strengthens willpower and helps us reshape our lives.