The monograph "Keystone Doctrine Development in Five Commonwealth Navies: A Comparative Perspective" explores the evolution and application of maritime doctrines across five Commonwealth navies. Authored by a distinguished desk officer at the Australian Defence Force Headquarters, the study examines the development and implementation of key doctrines within these naval forces, highlighting the similarities and differences in their approaches. By analyzing doctrine across the executive, operational, and training dimensions, the work provides insights into how each navy adapts to contemporary challenges and strategic demands. The comparative perspective offered in this study aims to enhance understanding of naval doctrine development and its impact on operational effectiveness. This monograph also reflects the author's extensive research and contributions to the field of international relations and military studies.