The Moomins are troll-like characters from a Finnish children’s book series that became popular around the world in the 1950s. But they never really took off in the United States. The author Tove Jansson rejected Walt Disney’s offer to buy the brand. Now, a bookstore chain in the US is trying to popularize the Moomins here. Will Coley reports on the themes in the Moomins series and why they continue to find new audiences.