'This new book by Richard Day is a very impressive compilation of research records, spanning a period of forty years or so, by him, his former students, and his research associates. The book shows how he has relentlessly explored economies far from equilibria, and to quote from one of his sentences by 'going against the prevailing disciplinary trends of over-reliance on the concept of equilibrium'. In the book, he emphasizes his conviction that economic optimizing and equilibrium analysis by themselves provide an inadequate mental image of the real world. I am in total agreement with him when he focuses on evolving markets, punctuate equilibria, and endogenously generated structural changes.' Masanao Aoki, UCLA