This paper is based on a compilation of the first two phases of longitudinal research on desegregation effects now being conducted in the Kalamazoo Public Schools. The purpose of the Phase I study was to obtain baseline data during the spring of 1971 prior to the desegregation of the Kalamazoo Public Schools, which was initiated in the fall of 1971. Baseline data were collected for classroom verbal interaction patterns, student opinions, and student leadership status. Student achievement data were also available through the regular testing program of the Kalamazoo Public Schools. The purpose of the Phase II study was to make longitudinal comparisons based on data collected prior to desegregation during Phase I and data collected after approximately one year of desegregation in the spring of 1972. Comparisons were based on measures of the following variables: (1) classroom verbal interaction patterns; (2) student opinions; (3) student leadership status; and (4) student achievement. Additionally, parent opinions pertaining to desegregation were studied. In Spring 1971, the Kalamazoo Public School system was in a unique position in that it was the only school system roughly representative of the black-white racial composition of the United States to attempt system-wide desegregation through two-way busing. (Author/JM)