Books on Zen are difficult to read and review. Since the nature of Zen cannot be described with words, using words to describe it is, at best, circumspect. As a result, Zen books tend to either err on the side of being obscure, impenetrable, and unhelpful for beginners, or on the side of being pop-spiritual works, New-Agey and innocuous. Moreover, too many books with "Zen" in the title are not written by experienced, knowledgeable practitioners. In the worst cases, the word "Zen" is used as a sort of catch-all for anything mystical or vaguely paradoxical.
Fortunately, The Eight Gates of Zen walks that narrow path between being obscure and blase. Written by John Daido Loori, who founded the Zen Mountain Monastery in New York. He was one of the great ambassadors who brought Zen to America, and also a great teacher. In The Eight Gates of Zen, he wrote an excellent primer to Zen in general and to the approach of ZMM in particular. The Eight Gates are eight facets of Zen practice that are central to monks, students, and lay practitioners at the monastery. Anyone, from the most experienced teacher to a new beginner, can engage in the eight practices.
Perhaps the most useful element of the book is the very clear, concrete instructions that Daido provides for zazen, which is sitting practice. Zazen has been taken over by pop culture images of smiling people in robes chanting "OM," but most people, when they attempt to start sitting, worry they are "doing it wrong." The instructions in this book are clear and simple (although zazen is simple, it is not at all easy!).
In the afterword at the end, the writing starts to become a little more abstract and difficult to follow. But by that time, the reader has been adequately prepared to advance to new levels of understanding. Finally, end of the book provides a suggested reading list for further exploration into Zen.
I had the good fortune of attending an Introduction to Zen retreat at ZMM several years ago, when I first received this book. Revisiting the text now, I can say that The Eight Gates of Zen is an accessible and practical entry point for those interested in Zen practice.