In 1986, New York City's summer Preparation for Raising Education Performance (PREP) program operated for the fifth consecutive year. Summer PREP is designed to ease incoming students' transition into high school and to provide instruction in basic writing skills. The program also provided theme-based instruction, enrichment, and guidance services to incoming Chapter 1-eligible students in grades 9 and 10, plus limited English proficient (LEP) and special education students already in high school. During the summer 1986, the program served a total of 5,246 general education, 2,577 LEP, and 760 special education students. The instructional program consisted of a one-hour language arts class plus two other one-hour special interest classes four mornings each week, and a fifth morning was devoted to educational excursions. The 1986 program clearly met its objective of helping students improve their writing skills. Although overall attendance was relatively good, individual class sizes were somewhat smaller than expected. Evaluation findings suggest that a summer program with clearly defined focus is an effective method of helping students improve their skills in a relatively short period of time. In the future, it should be determined if resources are being used as effectively, and student mentors should receive additional training in their role as teacher and peer mentor before the summer program begins. A School Participation Guide is included. (KH)