Robert Johnson's 2006 "Spying For Empire" is an impressive exploration of "The Great Game in Central and South Asia, 1757-1947." Johnson's focus is the slow growth of British intelligence activities in defense of the British Empire in India, and their effects on the similarly slow growth of a professional British intelligence service.
Johnson is hampered by the limited, sketchy documentation available on these early intelligence activities. However, he succeeds in presenting an intriguing portrait of the struggle by British authorities to understand the threat to India posed by Russian expansion in Central Asia. This struggle was made doubly difficult by an near-complete lack of European knowledge about the terrain Northwest of India. As Johnson makes clear, much of the early British reconnaissance effort was devoted to gaining such basic information as what passes over the Hindu Kush, Pamirs, and Karakorum Mountains might be feasible invasion routes.
As Johnson also documents, British intelligence activities were hampered by lack of a trained intelligence corps. A series of more-or-less gifted amateurs, mostly military officers, led the way, assisted by a variety of Asian agents who did much of the actual gathering of information. The work was incredibly dangerous; bandits, hostile tribesmen, cranky Khans and Russian patrols took their lethal toll of the officers and agents.
Johnson's account makes for dense reading, as he covers nearly two hundred years of turbulent history in South Asia in just 250 pages. The chronological approach to the material requires the reader to cover a huge swath of geography, for example from London to Southeast Asia, in each segment of the book, without the benefit of detailed maps. A general reader without prior knowledge of the British Raj may be challenged to understand the context of politics in India.
This book is highly recommended to those with an interest in the intelligence business and in the history of South Asia.