Five go to Demon’s Rocks. Illustrated by Eileen Soper. London: Hodder, 1961. First Edition. Good copy in chipped dust jacket.

The famous Five become involved in an adventure of undersea tunnels, a treasure trove of gold coins, and some ruthless villains, prepared to do anything to claim the fortune stored beneath the Lighthouse on Demon’s Rock. 

The 18th Famous Five book.