This book presents a collection of essays on foundational and methodological issues in cognitive science. Topics range from the philosophical problems surrounding intentionality and holism to specific scientific issues concerned with the architecture of systems for problem solving, planning, language processing, vision and visual-motor coordination. The larger theme is cognitive architecture and the twelve chapters show the generality of the problems associated with this theme as it impinges on almost every area of cognitive science and most methodological approaches adopted to date.