Book excerpt: This book presents a model for examining problems of institutional change and applies it to American economic development in the nineteenth and twentieth centuries. The authors develop their model of institutional change. They argue that if external economic factors make an increase in income possible but not attainable within the existing institutional structure, new organizations must be developed to achieve the potential in income. Their model is designed to explain the type and timing of these necessary changes in institutional organization. Individual, voluntary cooperative, and governmental arrangements are included in the discussion, although the latter differs considerably from the first two.