Contrary to a lot of popular mythology, the designs of popular products and successful systems do not appear suddenly, or magically. The authors believe that symbolic representation, and related problem-solving methods, offer significant opportunities to clarify and articulate concepts of design to lay a better framework for design research and design education. Artificial Intelligence (AI) provides a substantial body of material concerned with understanding and modeling cognitive processes. This book adopts the vocabulary and paradigms of AI to enhance the presentation and explanation of design. It includes concepts from AI because of their explanatory power and because of their utility as possible ingredients of practical design activity. This second edition has been enriched by the inclusion of recent work on design reasoning, computational design, AI in design, and design cognition, with pointers to a wide cross section of the current literature.