The cortically projecting cholinergic neurons found in the basal forebrain have been shown to be critical for normal information processing. However, to achieve understanding of information processing it is necessary to consider the basal forebrain not as an autonomous structure with a solitary task, but one that plays an integrative role, a structure connected intimately with many brain regions, interfacing cognitive and reward functions with motor outputs. It is from this integrative and functional perspective that the conference held May 1990 in Chicago, and this proceedings volume, were organized.