On 20 August 1917, the British government declared that its Indian subjects were to be granted greater participation in India's self-government. But there was another declaration that day, which removed the bar that then existed on Indians being admitted into the hitherto wholly British higher officer corps of the Indian Army, thus inaugurating its Indianization. In this book, Chandar Sundaram sheds new and important light on the story of the Indianization of the Indian Army's officer corps, by detailing its origins, from when it first appeared as an idea, to its acceptance, if only theoretically, by officials in London and New Delhi a hundred years later, in 1917. Sundaram breaks new ground by carefully treating the evolution of the Indianization idea in the 19th century, the various schemes it generated, and the reasons why they were not accepted. The Imperial Cadet Corps, which was the first Indianization scheme to be implemented, is then comprehensively analysed, as is the main reason for its failure. The commissions that were granted through the corps to Indian princes and gentlemen did not entitle them to command troops. Sundaram then shows how the corps' failure renewed the Indianization debate. This, in conjunction with India's enormous 1.3 million man contribution to the Allied effort in the First World War, led to the final acceptance of the principle of Indianization. Finally, Sundaram shows how features of the pre-1917 debate, such as such as racism, 'social difficulties', experimentalism, aristocratism, the 'martial races' ideology, and other forms of foot-dragging, fundamentally influenced the playing out of post-1917 Indianization policy. Only the exigencies of a second world war finally forced Britain's hand. Rigorously and painstakingly researched from archival sources in the UK and India, and written in a direct, jargon-free and engaging narrative style, this book is a defining contribution to the history of the colonial Indian Army, and will be of interest to historians of the British Empire, Colonial South Asia, and war and society, as well as to the general reader of military history.