Eugen Herrigel was a German philosopher who taught in Japan in the 1930s. Herrigel wrote a little book called Zen in the Art of Archery. It is about a different kind of archery, where hitting the target is secondary to the focus and awareness the archer brings to the task.
The essence of the story begins when Herrigel says, "Why I took up Zen, and for this purpose set out to learn the art of archery, needs some explanation." He then discusses his trials and the reward of his practice, which is in reality a spiritual quest. 
The book ends with Herrigel's teacher saying to him, "You have now reached a stage where teacher and pupil are no longer two persons, but one.
"You can separate from me any time you wish. Even if broad seas lie between us, I shall always be with you when you practice what you have learned."
The most celebrated quote from Zen in the Art of Archery is, "In the case of archery, the hitter and the hit are no longer two opposing objects, but are one reality." It points to the experience others have since described as "flow" or being "in the zone."
Zen is taught in many ways: calligraphy, art, gardening, tea ceremony, and in the case of this book, archery.
Zen in the Art of Archery is one of the most popular books on Zen Buddhism. Another excellent introduction is Zen Mind, Beginner's Mind by Shunryu Suzuki.
