The purpose of this program, which builds upon the success of a previous teacher enhancement effort, is to develop a leadership program that can serve as a national model for dissemination of knowledge and pedagological techniques in the subject areas of The Nature of Science and Evolution. The objectives of this program are 1) to improve the quality of instruction of the nature of science and evolution; 2) to encourage and enable biology teachers to begin with these matters and to integrate them throughout the biology course; 3) to demonstrate how the use of humans as biological examples can enhance student interest and learning; 4) to assist teachers in developing a more dynamic teaching methodology. Applications will emphasize a shift in laboratory focus toward exploratory activities. In addition the use of cooperative learning, concept mapping, and textbooks as reference sources will be encouraged. Specifically, 890 teachers from the mid-western and western United States will participate in the program. The objectives will be accomplished by three distinct, but related, program elements. First, 30 teachers per year will participate in an "Evolution and the Nature of Science Institute" (ENSI) and two followup sessions, to be held at San Jose State University (SJSU) for the first three years of the program. Second, six teams of lead teachers will be selected and trained in a "Lead Teacher Preparation Program" (LTPP), during each of the first three years of the program. Third, the lead teacher teams will present two- week satellite ENSIs (SENSIs) during the second through fifth years of the programs. It is proposed that 40 SENSIs be held, for twenty teachers each, at sites throughout the midwest and western United States. The total cost share of this program is estimated to be 42 % of NSF cost.