When Dr. Katherine Tansley's "Vision in Vertebrates" appeared in 1965, it filled a real void that had hitherto existed. It did so by serving at once as a text-book: for an undergraduate course, a general introduction to the subject for post-graduate students embarking on research on some aspect of vision, and the interested non-specialists. Gordon Walls' "The Vertebrate Eye and It. s Adaptive Radiation" and A. Rochon-Duvigneaud's "Les Yeux et la Vision des Vertebres" have served as important sources of information on the subject and continue to do so even though it is 40 years since they...