The Treasure of Mystery Island is a novel about The Brady Bunch. It was first published by New American Library in 1972.
Summary[]
The Bradys take off for Mystery Island and what is supposed to be a relaxing, fun vacation. But, unknown to them, there are mysterious forces at work on the Island and it isn't until they arrive that they find out about a missing treasure. Then it's up to the family to solve the puzzling riddle and find out the real truth about the Island.