The book Sandokai, the second volume of the Zen Text Library, is one of the fundamental original texts of Zen. It deals with harmony with the cosmic order, the merging and perfect unity of essence and appearance, emptiness and form, unity and diversity. It encompasses the entire depth and richness of the Zen teaching tradition. This text provides an essential key to understanding Zen. Without the explanations of a master, the text remains closed to the reader and its significance undiscovered. Until now, this text has been little known in Europe, but it will help the reader penetrate the true essence of Zen while also getting to know the authentic teachings of a Zen master.