This volume is a collection of papers on brain mechanisms which integrates theory and experiment to place visual information within the context of the action systems which use it. The book stresses both the intrinsic interest of frog and toad as animals in which to study the neural mechanisms of visuomotor co-ordination and the importance of comparative studies with other organisms. The book demonstrates the interaction between theory and experiment in neuroscience, complementing current data with a rich array of models which together constitute Rana computatrix, the "frog that computes". High-level schema models show the basic functional interactions underlying visuomotor co-ordination, testable by lesion experiments. Neural network models address data from neurophysiology and neuroanatomy. Although the stress in the modeling is on Computational Neuroscience to understand neurobiological phenomena, the results have implications for Neural Engineering, the use of ideas inspired by the study of the brain to design highly parallel, often adaptive, machines.