The Twenty-One Balloons by William Pene Dubois
What a peculiar story! William Sherman, tired of teaching ungrateful children, decides to travel around the world in a hot air balloon. Sherman succeeds, but not in the way he'd anticipated.
Unexpectedly, Sherman crashes on the island of Krakatoa. Instead of finding a deserted island, however, he comes upon a strange community of people. The community has a source of wealth, a magnificent diamond mine, that allows the people to do anything they wish. The people have created a zany civilization founded upon the idea of restaurants, eating out at a different family's restaurant every night. Sherman is shown novel designs for homes and odd inventions that have come from the clever minds of the island's residents. Despite their apparent creativity and great wealth, the people choose to live on an island that, every hour of the day, threatens their lives.
And, of course, as one might expect, the moment comes when Krakatoa blows. Somehow, the people are able to escape without harm and Sherman is able to return home to San Francisco.
Very, very peculiar book.
And what an odd coincidence that Twenty-One Balloons is my twenty-first book of the year!