AbstractScholars from various disciplines have contributed volumes of research aimed at improving the performance of individuals, processes, and organizations. With so many disciplines represented, human resource development (HRD) lacks a unifying model that practitioners and scholars may use to integrate and understand HRD issues. The Rummler and Brache nine‐cell performance variables matrix (1990) is used as a template to identify, classify, and describe major HRD scholars. In addition, a summary of the contributions made by the selected scholars is presented. In total, the comprehensive HRD model offers scholars and practitioners a synthesis and integration of the work of scholars from the disciplines that support HR