Strictly speaking, this little book by the Vietnamese Zen master Thich Nhat Hanh is not about Zen. It's more of an introduction to mindfulness and Mahayana. But in the West, this seems to be the book that everyone reads before they show up at the Zen center.
I read a review of A Miracle of Mindfulness that said it was not about Buddhism. It is; it's just written in such a way that non-Buddhist readers might not recognize that it's about Buddhism. Certainly it's a book that can be appreciated by non-Buddhists. But for me, it was the book that told me Buddhism might be my religion.
Most of all, this book holds out the hope that practice can be integrated into anyone's life, no matter how bleeped up it is.
This book is as close as you're going to get to a nuts-and-bolts explanation of formal Zen training. It's wonderfully clear and keeps Zenspeak to a minimum, yet there's depth to it as well.
I recommend this book in particular to people in the "why do I need a Zen teacher to do Zen?" phase. Of course, you don't need a Zen teacher. You don't need to brush your teeth or tie your shoes, either, unless you want to keep your teeth or not trip over your shoelaces. It's up to you.
This book explains zazen, the Zen teacher-student relationship, Zen literature, Zen ritual, Buddhist morality, Zen arts (including martial arts) and how all of these tie into the everyday life of a Zen student, in or out of a monastery.
Robert Aitken is one of my favorite Zen teacher-writers. His explanations of even the most vexatious koan can be wonderfully accessible.
Taking the Path of Zen covers much of the same territory as Daido Roshi's Eight Gates of Zen. The difference is that Aitken's book might be better for someone who's already got a foot in the door at a Zen center. In the Preface, the author says "My purpose in this book is to provide a manual that may be used, chapter by chapter, as a program of instruction over the first few weeks of Zen training." It does, however, provide a nice preview of what the first few weeks of Zen training are like.
4. Other Books Not for Beginners
Nearly all "beginner" Zen book lists contain some books that I'm not putting on this list, for various reasons.
The first is Shunryu Suzuki's Zen Mind, Beginner's Mind. It is a wonderful book, but in spite of the title it is not a good book for beginners. Sit one or two sesshins first, and then read it.
I am ambivalent about Philip Kapleau's Three Pillars of Zen. It's very good, but it gives the impression, I think, that the koan Mu is the be-all and end-all of Zen, which is very much not the case.
Alan Watts was a great writer, but his writings on Zen don't always reflect a clear understanding of Zen. If you want to read Watts's books on Zen for fun and inspiration that's fine, but don't read him as an authority on Zen.