This book is more than just a translation of a text. There is also much commentary by the author on the history of yoga.

I have read a lot of material regarding Vajrayana and Hinduism, but this book ranks all the way amongst the best. This book is much more than Kechari mudra (Kechari mudra simply happens to be one of the oldest practices in yoga). This book has much information about yoga in general. If you are into yoga, Vajrayana etc. GET THIS BOOK!

I came across this book from a discussion thread on aypsite dot org

Khechari is said to be the King of Mudra and it creates tremendous effect on one's conscious as it channel all the energy towards the all-seeing eyes the Ajuna Chakra. I learn a few things from according this book.

Nevertheless, it is just book talk untilI have experiential knowledge and be it.

#1 There is something called the Khechari Mantra

#2 One can flood the body with Amrta

#3 The use of drug (herb)

In #3 there is one particular practice that caught my eyes.

One will enter a dark cave and only consumes herb or medicinal pill or concoction of some sort. This is very similar to the Tibetan Dark Retreat with Chu-Lan(spelling?) In the Tibetan practice, it gradually prepares oneself towards consuming only the element aka Breathian

and this practice can eventually lead to the Supreme rainbow body of light. It will be great if there is living human master can show this practice.

This book is interesting to anyone even contemplating kechari mudra, a hatha yoga practice that amounts to inserting the tongue up behind the soft palate. It is a translation of a hathayoga scripture with associated notes which are very interesting field notes from his travels to India, and other explications, by the author on the practice of Khechari mudra. This scripture is a very significant text on this very important hathayogic tantric practice. Highly recommended.