The Book of Five Rings by Miyamoto Musashi

A major influence in the writing of Zen Guitar. Musashi was a legendary samurai in Japanese history, as well as one of its most revered artists and craftsmen. His 17th century book is a classic treatise on strategy and swordsmanship. But of course, the the sword here is just a metaphor. Everything in the book has broader meaning. I recommend the book in this translation by Nihon Services Corp. In my view, it's far superior to the other four translations available.

Zen in the Martial Arts by Joe Hyams

A good, simple intro to some fundamental zen ideas, and very easy to read. Hyams was a student of the famed martial artist Bruce Lee. Even if you have no interest in the martial arts, the ideas he talks about apply to anything. This is usually the first book I recommend to people who know nothing about zen.

Tea Life, Tea Mind by Soshitsu Sen XV

In Japan, the tea ceremony is a symbol for all human relations. To learn the tenets of the tea ceremony is to learn how to conduct yourself in the world at large. This is an excellent intro to zen aesthetics by Japan's master of the tea ceremony, worth digging up even though it's out of print. Another simple-but-deep book that's very easy to read.

Zen Word, Zen Calligraphy by Eido Tai Shimano and Kogetsu Tani

A beautiful book that combines the of zen calligraphy of Tani with "teaching commentary" by Shimano that draws out the meaning of each calligraphy in a short zen lesson. An excellent, easy intro to some key zen concepts, although again, it seems to be out of print. Given the exquisite nature of the calligraphy, I much prefer the oversize hardcover edition (the paperback doesn't do justice to the artwork).

 The Tao of Zen by Ray Grigg

If you want to understand the history of zen--where it comes from and the origins of its ideas--I highly recommend this work by Grigg, both for its insight and readability. Grigg shows how the essence of zen evolved out of Chinese Taoism, and clearly delineates the differences between "pure" zen and Zen Buddhism. Written in a way that even nonscholars can understand.

The New Lao Tzu, a contemporary Tao Te Ching by Ray Grigg

According to legend, the sage Lao Tzu wrote this classic summary of wisdom known as Tao Te Ching about 2,500 years ago. Its enigmatic, mystical essence serves as the foundation of Taoism, and thus, zen. As many translations of this landmark work abound as the Bible. But I like Grigg's because doesn't go for a literal reading of the text. Instead, he tries to capture its essential wisdom in language that speaks directly and poetically to the modern reader.

 Seeds From a Birch Tree: Writing Haiku and the Spiritual Journey by Clark Strand

A good intro to the art of writing haiku, the three-line, 17-syllable form of zen poetry. About a year ago I received an advance copy of the book and was asked to offer a blurb for the book jacket. I wrote, "In everything ordinary lies a poetic truth, and Strand shows us how to find it. Reading Seeds From a Birch Tree, I felt as though I were watching the bloom of a cherry blossom--so brief, so beautiful, so simple, so profound."