
I'm pretty sure I would have liked this as a child, too - I loved Jules Verne (especially Twenty Thousand Leagues Under the Sea), and this reminded me a lot of that, though The Twenty-One Balloons was a lot more light-hearted. Also, my eleven year old son enjoyed The Twenty-One Balloons as much as I did, and our tastes don't overlap that much. So I'm going to go out on a limb and say that this book should appeal to a pretty broad audience. In fact, I think it is definitely an under-appreciated, underrated classic.
William Pène du Bois' quirky, rambling writing style appealed to me as much as the story did. Who wouldn't like "a balloon in which I could float around out of everybody's reach....to be where no one would bother me for perhaps one full year" (p. 40), at least on some days?
This story of 66-year-old retired mathematics teacher Professor William Waterman Sherman, who stumbles on a secret society on the supposedly uninhabited Pacific island of Krakatoa just before its 1883 explosion, is definitely one of the most whimsical Newbery winners I've read. There's a lot about balloons; their construction and their lifting power and the mechanics of rigging a basket, a couch, a house, and a huge platform up to them. There's economy, government, and exotic restaurants, and kids who get to invent incredible things. It's a great mix of science and fantasy, appropriate for all ages. Why isn't this book better known?
Funnily enough, my family just watched a Mythbusters episode (Larry's Lawn-Chair Balloon- myth confirmed) about a guy who attached a lawn chair to a bunch of weather balloons. And tonight we're going to check out Heliosphere, an "enchanting outdoor spectacle of aerialist performers suspended from a larger-than-life helium balloon" at Ann Arbor's Top of the Park festival, just to continue the theme.