I first read this book about ten or twelve years ago, when I was a member of a Zen community (probably about the time when I took the 10 precepts of a dharma teacher). Now I am a leading a mindfulness meditation community (part of the secular vipassana, or insight meditation tradition), and I find myself drawn back to some of the practices I first learned within the Zen community, and in particular the chanting.
Probably chief among the chants used daily in Buddhist communities world-wide is the Heart Sutra, which teaches the central and difficult concept of "emptiness." I felt it was time for me to take a refresher course, and picked up Mu Soeng's wonderful little book. Mu Soeng (he also wrote a book about the Diamond Sutra) was a monk in the same Zen tradition that I trained in (the [Korean] Kwan Um School of Zen), and he is quite a good scholar of the tradition and its teachings.
My re-reading after having left the book (and the Heart Sutra) aside for more than a decade was timely and highly enjoyable. My only quibble (and I ding him one star for this) is the author's attempt to insert ideas drawn from quantum physics into the mix; it's unnecessary and promotes a science-lite conflation of science with metaphysics or spirituality that can be misleading, at best. Aside from the bits and pieces of quantum woo, the presentation is clear and compelling. I highly recommend it to anyone interested in Buddhism, especially those who would like a good explanation of the rather esoteric concept of emptiness.
The Heart Sutra is quite amazing when put in light of Quantum theories. Mu Soeng does a great job in relating the two, and it is amazing to find out that over a thousand years ago quantum principles have been described by these simple (and yet so complicated) sutras.