The history of thought in the field of Economic Development and corresponding development programs have gone through a series of identifiable phases. Phases of theory and praxis in Agricultural Development are likewise compared. In both cases, there is an apparent lost opportunity to learn the lessons of past failures and successes before moving to the next fad. After reviewing several policy and program areas, a few lessons are synthesized, a forward-looking research framework suggested, and the appropriate role of foreign aid discussed. A particular theme of interest is the balance in thinking and programs between social engineering and facilitation of economic cooperation.