ABSTRACT
A commentator for this volume has the unique opportunity to review the most comprehensive analysis of the moon illusion in its 2000 plus-year history. As E. G. Boring (1942) has so succinctly pointed out, illusions serve to indicate what we do not know about perception and provide some clues for correcting this deficiency. The puzzle of the moon illusion is a challenge that has been effectively accepted by the contributors to this volume. However, this volume is concerned not only with the fascinating moon illusion but also with the present state of our knowledge about perception, particularly the mechanisms involved in perceived size.
