The book is essentially an account of the set of discoveries that Mike Brown made at the beginning of the past decade and how the discovery of Eris in particular led to the controversial defining of the word “planet” so as to exclude Pluto from the category. The book is very accessible to a general audience, avoiding technical discussions of planetary dynamics and even joking at one point about not knowing the definition of Barycentric Dynamical Time.
For me, the best part of the book was that it filled in the back-story behind the finding and naming of the objects that Brown discovered. Since the 2006 IAU conference that redefined what a planet is, I’ve paid a good deal of attention to those objects, but I didn’t know many of the particulars of their discovery and this book definitely helps fill in the details.
Mostly, this is an account of Mike Brown’s life during this period of discovery–he got married and had a daughter over the course of time that he was making the discoveries– and indeed his daughter was the chief focus of his life when the most dramatic events relating to the science were unfurling.
Brown’s view of the solar system is concordant my own. In summary, he sees the solar system as being dominated by the four outer planets, the gas giants, with the four inner planets of secondary importance. After that come the smaller bodies in the Kuiper Belt beyond Neptune, this group including Pluto and many of Brown’s discoveries, and the Asteroid Belt, which lies between Jupiter and Mars. Obviously, this is controversial to the many, many people who learned that the solar system had nine planets as a child, but I think that this view best captures the state of our solar system.
So, I would recommend this book to those who want a personal description of the process that uncovered the existence of dwarf planets like Sedna and Eris. If you want a more detailed description of the dynamics of solar system bodies past Neptune, I’d actually recommend Mike Brown’s blog, which he started last November.