Parallel distributed processing is transforming the field of cognitive science. "Microcognition" provides a clear, readable guide to this emerging paradigm from a cognitive philosopher's point of view. It explains and explores the biological basis of PDP, its psychological importance, and its philosophical relevance. Starting with a survey of the assumptions and methodology of classical AI "Microcognition" proceeds to a full treatment of the PDP alternative. It describes the main properties of PDP architectures with numerous examples and it explores the tangled question of their relationship with classical work, the theoretical significance of mixed PDP and classical models, and various criticisms of the models. Biological and evolutionary perspectives are also included. Of particular philosophical interest is the author's treatment of the relation between these computational models and ordinary talk of beliefs and desires, or folk-psychology.