In the 1860s, Captain Thomas Montgomerie trained natives to be surveyors, and had them explore the region covertly. These men, known as pundits, were disguised as lamas (holy men). This book talks about these servants of the Raj who managed to map the Himalayas and Tibet, helping the British to consolidate their rule in the Indian sub-continent.
Fact-filled book for anyone seriously interested in the Great Game and the pundits, but a little textbookish for most general readers. For much of the same material in a more entertaining format, I'd recommend Peter Hopkirk's classics Trespassers on the Roof of the World and The Great Game.
One cannot find a more fascinating subject than spying for the British Raj in that exotic regions of Central Asia, the Pamir and above all, Tibet in nineteenth century. It is hard to write its account that is not interesting. So interesting the book is.
However, rather than a continuous, unbroken narrative of adventures of ordinary men that "Pundits" were, the book is unimaginatively broken up in sections,, roughly one each for the spy or surveyor. One fails to get a bigger picture and sense of causality. The inter-related nature of of the expeditions gets buried in a disjoint record of individual exploits.
Otherwise, a very informative and rather complete story.