For a lot of kids, childhood is just a period of jumping from one hobby to the next. It could be anything: minerals, bulldozers, Pokémon, dinosaurs. It consumes you for a short while in adolescence then fades away as quickly as it came.

For me, that hobby was 20th century military history. In case you need someone to tell you, that’s odd. This is not a hobby impressionable young children should be into—least of all sheltered, red-haired suburbanites like myself. It’s too complex, too dark. And yet, before I hit the age of 13 I had read all the major Stephen Ambrose books, as well as key titles like The Guns of August, Hiroshima, and Stalingrad. Very nerdy stuff for a preteen.

I can recall, at the peak of my historical promiscuity, researching the number of surviving World War I veterans on a clumsy HP desktop with a dial-up connection. This was around the turn of the century, so there were still a few veterans left (the last, Frank Buckles, died in 2011). It dawned on me then, in the way only a dimwitted 11-year-old could realize, that eventually each and every one of these veterans would be dead. That’s a sobering thought—to realize that the arc of history, which I was just then coming to appreciate, applied with equal measure to the lineage of generations. They are all equally subject to that tyrannical arrow of time.

Fast-forward 15 years and every veteran of the war is dead. I’m 26, and I’m visiting my mother in the quaint suburban town of my upbringing. She hands me a scrappy old legal pad written through in faint pencil. The entire thing is about a hundred pages long, and every line, every space, even the backs of some of the pages are filled with ornate, delicate cursive. She looks at me with a slight grin and says…