The book is structured into four distinct sections, each offering a different window into Zen thought:

is a highly regarded classic that has served as a foundational introduction to Zen Buddhism for Western readers since 1957. Compiled by Paul Reps and Nyogen Senzaki , the book is essentially "four books in one," curated to provide direct access to primary Zen and pre-Zen sources through parables, puzzles, and poetry.

: A classic 13th-century collection of 48 koans (paradoxical puzzles). These are designed to "confound reason" and break through logical thinking.