A comprehensive and stimulating study which presents the views of 71 leading theorists on the underlying mechanisms and functions of the primary visual cortex. Current methodological strategies for model building and assessment, suitable for dealing with relatively simple physical systems appear inadequate to cope with the more complex, self- organising, goal-directed systems studied in the behavioural and brain sciences. This book does not attempt to elucidate a definite 'correct' model of the visual cortex but rather reflects differences in people's ideas and preconceptions about the overall function of the visual system and deeper issues about scientific goals and methods. The chapters are placed in approximate (but by no means monotonic) order of level of description, starting with overall function and running through to detailed microanatomy, and are only mathematically rigorous to the level of calculus. The final chapters suggesting directions for future research place in context a fascinating area of study which will continue to interest psychologists, physiologists, anatomists, neuroscientists, cyberneticians and researchers in artificial intelligence for many years to come.