Ghadir Khumm: One of Islamic History's Best Kept Secrets sheds light on the pivotal event of Ghadir Khumm, an occasion often overlooked in mainstream historical discourse, yet critical to understanding the foundation of leadership in Islam. On the 18th of Dhul-Hijjah, during the return from the Farewell Pilgrimage, the Prophet Muhammad (PBUH) declared Imam Ali (AS) as his successor in front of thousands of companions. This book meticulously examines the historical, theological, and political implications of this event, exploring why it remains one of the most significant yet understated moments in Islamic history. It provides an in-depth analysis of the sermon delivered by the Prophet, the reactions of the companions, and the role of Ghadir Khumm in establishing the principle of Imamah (divine leadership). The book also discusses how the event has been treated in both Sunni and Shia traditions and its relevance in contemporary Muslim thought. Through thorough research and referencing, this work uncovers the importance of Ghadir Khumm and why it remains a key element in the discourse on Islamic leadership and authority.