A larger solar system [Eise Eisinga].- Eleven planets [Giuseppe Piazzi, Johannes Kepler, Johann Elert Bode, Baron Franz Xaver von Zach, Heinrich Olbers].- The writing desk planet [Elaine Mac-Auliffe, Olin Eggen, George Biddell Airy, John Couch Adams, Urbain Jean-Joseph Le Verrier].- 'I've found your Planet X' [Carl Lampland, Clyde Tombaugh, Percival Lowell, William Pickering].- The kid planet [Venetia Phair-Burney, Venetia Burney, Herbert Turner, Falconer Madan].- A strange and wonderful week [Jim Christy, Bob Harrington].- Fortunate circumstances [Marc Buie].- Nix and Hydra [Max Mutchler, Andrew Steffl].- The unauthorized planet [Charles Kowal].- Uranus: problem solved? [Myles Standish, Tom Van Flandern].- Mysterious forces [Giacomo Giampieri, John Anderson].- The hunt for the Death Star [Richard Muller, Marc Davis, Piet Hut].- The secret planet [Zecharia Sitchin].- Vulcanoids and Earth-grazers [Dan Durda, Alan Stern, David Tholen].- The Kuiper connection [Gerard Kuiper].- Comet puzzles [Martin Duncan, Jan Oort, Julio Fernández].- Smiley [Dave Jewitt, Jane Luu].- Family portraits [Chad Trujillo].- The migrating planet [Renu Malhotra, Wing-Huen Ip].- Icy treasure troves [Dale Cruikshank, Carl Pilcher, David Rabinowitz].- The big five [Mike Brown].- The tenth planet.- The Spanish invasion [Pablo Santos-Sanz, José-Luis Ortiz, Reiner Stoss].- Pas de deux [Robin Canup, Bill McKinnon].- Model from Nice [Hal Levison, Alessandro Morbidelli].- Planet under siege [Brian Marsden, Mike A'Hearn, David Levy].- Planetary elections [Owen Gingerich, Jocelyn Bell Burnell].- The continuing story [Patsy Tombaugh].- A thousand planets [Alan Stern, Brett Gladman].- New Horizons.
