This book is a brief and incredibly useful overview of the main body of Mahamudra meditation, and I would enthusiastically recommend it to any practitioner of Mahamudra, with any degree of experience. It contains the kind of direct, practical advice that can be rather difficult to tease out of traditional presentations that rely heavily on scriptural citations. The author is obviously a lama of considerable experience and his suggestions gave me insight even into foundational practices I've been engaged with for many years.
I would also highly recommend this book to anyone in the Soto Zen lineage practicing shikantaza, or any Zen practitioner engaged in a form of silent illumination. The similarities between Mahamudra and these approaches are both obvious and pervasive, and if you've ever been frustrated by the lack of detail in instructions like "think not-thinking", this book will probably have a lot to say to you.
This book contains some decent instructions, but overall it is too vague and lacks phenomenological precision. It is not precise enough to work with in a way where you have certainty. Rather, you must interpret a lot for yourself and have perhaps several parallel interpretation streams running at once as to what is being conveyed.