Zen Mind, Beginner's Mind - Shunryu Suzuki
This series of lectures by Zen Master Shunryu Suzuki is considered a classic of Western Buddhist literature. Suzuki's Buddhism has been called 'ordinary' – his teachings are not about trying to attain enlightenment. Instead, they are about keeping an open mind ('beginner's mind') and the right attitude in order to maintain a practice of meditation. Read this book if you are just starting on the Zen path, or if you've been practicing for years, or even if you are not a Buddhist at all – everyone can find something in Suzuki's teachings (it's also a book that stands up very well to re-reading).