Yoga nidra literally means “yogic sleep,” and it’s a technique in which one systematically pursues a high degree of relaxation. Still, it’s a bit of a misnomer in that one doesn’t actually fall asleep. In theory, that is, most practitioners will have the experience of falling asleep at some point in practice. That’s because one is entering a hypnagogic state in which one is on the leading edge of falling asleep. It’s not always easy to stay on one side of that line (without being excessively mentally aroused.) The practice is typically done with a teacher who verbally instructs the students (live or via a recording)—because it’s quite hard to keep the sequence straight without an excessively high level of mental arousal—particularly for new practitioners.
This 8-stage practice has multiple purposes. One is simply to achieve a relaxed state. Note: it can be successfully used with individuals who suffer from insomnia, but with the notable risk that they may have trouble not falling asleep during the practice if they come to associate yoga nidra too strongly with sleeping. I know that I—who could never sleep in planes or on buses—found it useful for getting sleep when one’s mind tends toward an overly mentally aroused state. The technique is also used to tap into the subconscious. If you’ve ever noticed the strange imagery that pops up as one is going to sleep, you are witness to the subconscious at work.
The book is divided into three parts. The first part offers background on the topic. It describes both yogic and scientific explanations for the working of this practice and its sequential arrangement. The middle part describes variations on the practice, including scripts. While I mentioned that the basic approach consists of 8 stages that are sequentially arranged, there are many ways to vary the practice depending upon how much time one has and what one’s specific objective is. So the middle part describes several options including one optimized toward children (who have slightly different needs due to cognitive development.) [FYI: the eight stages are: 1.) Preparation for practice, 2.) Resolution (i.e. sankalpa), 3.) Rotation of awareness around the body systematically, 4.) Awareness of breath, 5.) Awareness of sensations /opposites, 6.) Visualization, 7.) Repeating one’s resolution, 8.) closing.] The final part delves deeper into scientific explanations of the state of yoga nidra and its health benefits.
There are four appendices that present research on yoga nidra with respect to: 1.) stress and heart disease, 2.) biofeedback, 3.) brain imaging, and 4.) altered states of consciousness. There is also a reference section arranged by topics. The book has many graphics from line drawn diagrams to color plates of brain scans (if one has a hard-copy or an e-format that supports them.)
I found this book to be extremely valuable. It’s definitely a guide book and its readability varies. It can be technical in places (but most laymen shouldn’t have a problem following it), and it can be repetitive in the middle where it’s mostly descriptions of variations on the practice. It does include stories in a few places, but is intended as a text rather than to entertain and so it’s not without some dry spots.
I’d highly recommend this book as a reference for those who teach yoga nidra. It will definitely expand upon (and help one keep straight) what one learned in teacher training and yoga nidra workshops.