Tyson is always a favorite guest on The Daily Show and this book was discussed on his last interview with Jon Stewart. Library to the rescue!
There are 9 chapters to this fairly short book, all done with wit and an obvious love of science. Tyson goes over Pluto's history, how Pluto was received in our culture, and the descent of how Pluto lost his status as our 9th planet.
Apparently Americans really love Pluto, not only because of it's association with Disney's dog, but because an American discovered Pluto back in 1930 by New Mexican Clyde Tombaugh, a 24 year old farmboy. Tombaugh lived to his 90s to see how Pluto was about to be reclassified and fought it tooth and nail. Ergo, America discovered a planet and it shouldn't be taken away.
The trouble with planets is...a definition for planets was never ever set in stone. In the '00s, the International Astronomical Union began devising a concrete definition for a planet. In 2006, it was determined that Pluto did not meet the new definition - mostly because it didn't clear its own orbit of debris.
This is an excellent book that makes science a lot easier to understand and offsets the jargon with comical letters from outraged children. Tyson has an opinion at the end that suggests a new way of teaching kids about the solar system so that its not only planets that get their day in the sun...so to speak.