When Zen Buddhism crossed from China to Japan in the twelfth century, it entered a phase of development that was not only to inspire a magnificent range of artistic achievement but also to exert a tremendous influence upon Japanese life itself and, eventually, to bring to the attention of the West a religious philosophy both unique and challenging in its power. First published in 1960, the purpose of this anthology is to suggest an approach to answering the perennial question 'What is Zen?'.