Occasional Paper #1, Four extension "systems" are compared and contrasted in this paper: the U.S. Cooperative Extension Service, the "typical system" in developing countries, the Training and Visit system, and the Farming Systems Research and Extension approach. While distinct in various ways one from another, interesting and useful insights can be gained through comparing and contrasting their purposes, organization, particular strengths and special problems. Extension is seen to have several discrete definitions and aims, varying structural arrangements and, hence, differing strengths and weaknesses. While organizational concerns may be the key factor for extension development experts currently working in LDC's, it is suggested that the linkage among educational, research and extension bodies remains a major factor for success in the overall agricultural development process.
