A study analyzed and compared four selected models in the cyclical tradition of group development as a basis for identifying possible issues and implications for future theory building. The theorists whose models were examined were Leland Bradford, Jack Gibb, William Schutz, and Theodore Mills. Both historical and conceptual perspectives of the cyclical tradition were investigated prior to analysis of the models. Analysis focused on concepts related to these aspects of phase development: (1) phase sequence, (2) forces that impel and impede developmental sequences, (3) changes that characterize phase development, (4) the nature and function of recurring phenomena, (5) dynamics of member relations that are specific to phases and cycles of development, and (6) the nature and configurational patterns of developmental flow. Concepts used to describe aspects of phase development and recurring phenomena in the four models were identified and explored through definitional analysis (analysis of the descriptive and operational adequacy of the concept) and, when feasible, through comparative analysis (identification of parallels and disparities among different models). Important inferences and implications from the study were drawn for four focus areas: group process problem concepts, the motive forces of group development, phase theory and developmental flow, and cyclical theory. (YLB)