1. What is a planet?
2. Seven perfect planets made of aether
3. The Earth becomes a planet
4. Sixteen planets
5. Not everything that orbits the Sun is a planet
6. Uranus!
7. The celestial police
8. Neptune, the thirteenth planet
9. Easy come, easy go
10. Pluto, the fourth ninth planet
11. Hidden secrets of the outer solar system
12. The plutinos
13. Is Pluto a planet?
14. Goldilocks
Postscript. Current thoughts by other astronomers
Appendix. What we know about Pluto.