As part of a research project on "Patterns of Successful Assistance in Urban School Improvement Programs," this paper presents a case study of an assister's work in the Constituency-Based School Renewal Program (CSR), implemented in an elementary school in Brooklyn, New York. CSR is a program aiming to institute a process by which a school will improve itself. The program lends resources and personnel support until the school is able to independently continue the improvement process. The school under study is located in a poor working-class neighborhood, with a student body that is 95% black and 5% Hispanic. It had lost ground in climate and achievement under a former principal, and the renewal program was then instituted. The paper describes the chronology of the assister's techniques for mobilizing the implementation of the CSR program in the school. His activities included forming a planning team and training them to work effectively with the whole school; helping the planning team to write a comprehensive improvement plan; and helping them to implement the plan. He remained available to act as a trouble shooter as problems arose. The results of this implementation of the CSR program included an improved school climate as a result of closer relationships between teachers, parents and support staff; the use of new products for curricular improvement; and an increase in student achievement. (CG)