Interviews with dozens of prominent astronomers based all over the world have resulted in stories of great literary value. The first is set in a surprising location: Franeker in the Dutch province of Friesland, where an eighteenth-century woolcomber and amateur astronomer called Eise Eisinga built a mechanical model of the six known planets on his living-room ceiling. This orrery, which is still in working order, was completed in 1781, the same year in which William Herschel discovered a seventh planet, Uranus. Eisinga’s work was therefore outdated even before it was properly finished.

This is exactly how science works. As soon as we think we know everything, a new and unexpected discovery comes along. The Hunt for Planet X is packed with triumphs and setbacks, each described from an original perspective, with an emphasis on the human angle. Dave Jewitt, for instance, even received threats after discovering a large brown dwarf beyond the path of Neptune, thereby undermining Pluto’s status as a planet.

This was merely the curtain-raiser to an astronomical soap opera surrounding Pluto. The climax to the story so far has been the discovery in 2005 of a distant celestial body called Eris, which turned out to be larger than Pluto. This presented astronomers with a dilemma: either Eris and Pluto were both planets or both would have to be accorded some other status. The considerable likelihood that many more ‘Erises’ are concealed in the depths of our solar system led the experts to opt for the latter: like Eris, Pluto is now designated a ‘dwarf planet’. But not all astronomers have reconciled themselves to the change and their difference of opinion has developed into an international drama, complete with intrigue, cheating and physical intimidation.

The Hunt for Planet X arrives with the search still in full swing, and reports of new hunting trophies will undoubtedly make future headlines. You need to read Schilling’s book, however, to find out what’s been going on behind the scenes.

• First popular science book to provide the full background to the ‘demotion’ of Pluto
• Firm focus on the people behind the discoveries
• A ‘scientific detective story’