An Introduction to Zen Buddhism is a really good introduction to the concepts of Zen, written by a Japanese person who had enough contact with the Western world to make an attempt to explain the unexplainable.
Zen: not as a belief system, but as an experience, a way of perceiving reality. For anyone interested in Kinbaku, this context matters. Zen thinking — with its focus on direct experience, presence, and non-duality — is present in many Japanese disciplines.
One of the world’s leading authorities on Zen Buddhism, D. T. Suzuki was the author of more than a hundred works on the subject in both Japanese and English, and was most instrumental in bringing the teachings of Zen Buddhism to the attention of the Western world.
Bibliographic information
Suzuki, Daisetz Teitaro. An Introduction to Zen Buddhism. New York: Grove Atlantic. Here is the link to the publishers' page.