The Twenty-One Balloons by William Pène du Bois was published in 1947. This book has stood the test of time. A retired school teacher sets off on a balloon adventure and ends up of an island  secretly populated with families of immense wealth- the island has a diamonds.  The author explores what different people would do if money was no barrier,  different families on the island pursue different things. Many of the ideas would have large appeal to children eg beds that makes themselves. An interesting read especially for boys.