The Pluto Files: The rise and fall of America's favorite planet, by Neil deGrasse Tyson
Tyson is an astrophysicist, Frederick P. Rose Director of the Hayden Planetarium, and lover of all things space like. When the opening of the remodeled Hayden Planetarium in 2000 created a hubbub about the status of Pluto in our solar system, Tyson became embroiled in a global kerfuffle about how to classify the furthest and most mysterious of the large bodies in our cosmic back yard.
Here's the problem: Pluto doesn't fit our current classification of planets. It's too small, smaller even than several moons we can observe from Earth. Its orbit around the sun is off kilter, and only matches those of other small objects far out in our system in the Kuiper Belt, none of which is considered a planet. It's the only "planet" made primarily of ice, with just a little rock thrown in. But, it is large enough to use its own gravity to remain a sphere, it has an atmosphere, and it has at least three moons. The International Astronomical Union reclassified Pluto as a dwarf planet in 2006, but the issue is not an easy one and public outcry continues to this day.
Although he logically thinks it shouldn't be considered a planet, Tyson found that Pluto is too deeply entrenched in the American psyche to be demoted. It was discovered by an American named Clyde Tombaugh in 1939, from an American observatory in Flagstaff, Arizona. Mickey Mouse's own dog is named after it, and Pluto's sheer quirkiness makes it the overall favorite of elementary school kids nationwide. The enthusiastic scientist explores the love we have for this wonky planet-that-isn't and leads us on a rollicking romp through the history of Pluto and the heated opinions abounding in the astronomical community.
Mirron Willis does a wonderful job bringing this book to life in the audio version, but I also encourage you to look at the paper copy for fantastic photos, fun cartoons, copied letters (including hate mail) from school children, and a real sense of science and fun.