Chitons form a peculiar and highly interesting class of molluscs, known with certainty to exist since the Ordovician, and widespread in all world seas to depths from 0 to over 7,000 m. In recent years taxonomists all over the world have much contributed to our knowledge of the chitons and their synonymy, so that the number of living species now amounts to some 800. The authors propose to not only compile all actual knowledge about the living chitons, but, where possible, a after a careful study of the type material, to systematically describe and illustrate every known -- or hitherto unknown -- species. In most cases the detailed figures are new and drawn by the senior author, P. Kaas. The Monograph of Living Chitons is planned to appear in ten volumes.