Dunlop was a District officer during the Indian Mutiny. In fact he was responsible for the town of Meerut where the first major outbreak took place. Fortunately for him, he was on leave in the Himalayas at the time, so was not murdered with most of his colleagues and friends. He also had no family to lose.
The book is the story of the first year of the Mutiny and his paricipation in an irregular cavalry force, modelled on the famous Guides regiment that he had seen at the siege of Delhi.
Some of his stories are quaint, some are blood curdling, some are frankly a bit irrelevant. Clearly, his own agenda was to make Britain aware of the hard choices that were being made in incredibly difficult circumstances. Hence the story sounds a bit apologetic.
What a modern reader may find most useful is the description of irregular warfare on the edge of society. There are echoes of American Civil War writings about units like Quantrill's Raiders. The courage is jaw dropping. Dunlop is on one campaign with an 'army' of about 100 men confronting 2,500 insurgents. The enemy leader is killed and then decapitated. Dunlop hastens to inform us that this was necessary, since unless they stuck the head on a pike for all to see the tribals would fight on!
Interesting, good for military buffs and social historians. Perhaps a bit unclassifiable for a general reader.