This monograph is dedicated to a timely yet insufficiently explored chapter in the history of British colonial policy. Drawing upon an analysis of a substantial body of scholarly works by both domestic and foreign authors—and utilizing unique, newly discovered documents from historical archives—the study thoroughly examines a complex array of issues. This examination serves to assess the significance, position, and role of the Persian Gulf—primarily within the context of the Middle Eastern policies of Britain, Germany, France, Turkey, and Iran—against the broad backdrop of international events.