Some children’s books seem to be timeless: Peter Rabbit, for instance, or Charlotte’s Web. Others are unmistakably a product of their Zeitgeist and become less accessible with each passing generation: it will be surprising if today’s bestselling author Judy Blume appeals to children in the year 2050 or so. In the case of G. A. Henty (1832– 1902), even the titles, with their potent whiff of Victorian imperial verve and muscular Christianity, are enough to elicit a condescending smile from modern readers: By Sheer Pluck: A Tale of the Ashanti War; or With Buller in Natal; or A Dash for Khartoum: A Tale of the Nile Expedition; or The Tiger of Mysore: A Story of the War With Tippoo Sahib.

Henry’s eighty historical adventure novels for boys (yes, for boys—it goes without saying that no writer today would get away ...