Much has been discovered in recent years about the way in which our visual system copes with very low light levels. This detailed and up-to-date book describes the light and dark adaptation of receptoral and post-receptoral mechanisms from a number of perspectives. The authors emphasise the importance of the study of achromatopsia, a rare congenital condition in which the visual mechanisms that mediate day vision are absent whilst those that mediate night vision remain intact, in isolating those parts of the visual apparatus which are normally associated with night vision. In addition, there is a comprehensive review of those ocular conditions which involve a loss of night vision. The final section of the book discusses the various types of night-viewing instruments presently available, against the backdrop of what limits night vision in normal observers. Contributions from many of the world's leading experts in vision research makes this unique volume essential reading for all those with an interest in night vision, including ophthalmologists, optometrists, neurologists, physiologists and psychologists.