This is the fourth publication in the series of Biological Sciences Curriculum Study (BSCS) Special Materials program with its emphasis on preparing teachers for teaching underachievers. The publication is divided into eight parts, providing adequate background on BSCS materials and procedures to be used by teachers. Included are three chapters discussing characteristics of underachievers, suggested instructional methods, teaching practices, and administrative procedures conducive to providing meaningful experiences for these students. Descriptions of BSCS "Biological Science: Patterns and Processes," designed for underachievers, are included in two separate chapters along with suggested programs for the preparation of teachers. A selected bibliography and listing of federal programs for support of BSCS Special Materials program are also provided. (PS)