The Young Visiters was published in 1919 but written in 1890, when its author was 9. It appeared with a Preface by J. M. Barrie and with the manuscript’s many spelling mistakes faithfully reproduced. Within two years it had sold 230,000 copies, given rise to a stage play, and caused a rumpus in literary London. It has never been out of print since. This is an exceptional record for a slight work. Why was The Young Visiters so popular and why does it endure?