Beatrix Potter’s tales about the frolics and misadventures of Peter Rabbit, Squirrel Nutkin, Jemima Puddle-Duck and other animals have charmed children around the globe for well over a century.

Potter had put aside the book in 1914, the year the world fell apart. At the time, the author was absorbed by recent marriage, her father’s terminal illness and by trying to make a go of hill ...