This book, by H. Gunaratana Mahathera, is an invaluable gift that you can use to inform your practice of meditation. The tradition is Theravadan Buddhist, but it is true to the spirit of Zen as well. The information is invaluable. "As more people turn to meditation, they need more simplified instructions so they can practice by themselves without a teacher around."

Zen Buddhist Books from Windbell Publications, the publishing arm of Dogen Sangha, a Buddhist community based in Tokyo and founded on the teachings of Dogen Zenji.

The whole book. Online. "What follows is based on actual occurrences. Although much has been changed for rhetorical purposes, it must be regarded in its essence as fact. However, it should in no way be associated with that great body of factual information relating to orthodox Zen Buddhist practice. It's not very factual on motorcycles, either."

Toward an Understanding of Meditation and Consciousness by James H. Austin, M.D.