2013 Reprint of 1942 Edition. Full facsimile of the original edition, not reproduced with Optical Recognition Software. Walls’ classic text is a comprehensive treatise on the eye in which he includes and correlates an immense amount of data on the anatomy and physiology of the eye in relation to the various environments in which it functions. The 689 pages of text are very readable, appealing to the interests of the biologist, clinician or lay reader, and constitute, therefore, a textbook on the eye. There are 197 illustrations throughout the book. Part one outlines the essentials of the vertebrate (human) eye, the histology and physiology of the vertebrate retina, and discusses scotopic and photopic vision. To this is added an account of the embryological and evolutionary genesis of the eye. Part two discusses the following topics: adaptations to arhythmic activity as seen in photomechanical retinal changes and in pupil mobility; adaptations to diurnal activity; adaptations to nocturnal activity; adaptations to space and motion; adaptations to media and substrates including aquatic and aerial vision; and adaptations to photic quality including color vision in animals, dermal color-changes, and coloration of the eye. Part three traces the history of the eye from the lowest to the highest living vertebrates. There is a 24-page bibliography and an index and glossary.