David Morrison is the head of space science research at the NASA Ames Research Center. He participated in the Mariner mission to Mercury, the Voyager mission to the outer planets, and the Galileo mission to Jupiter, in addition to astronomical studies of the planetary system. He received the NASA Outstanding Leadership Medal for his contributions to protection of the Earth from comet and asteroid impacts, and the Klumpke-Roberts award of the Astronomical Society of the Pacific for education and public service in astronomy. In additon to this book, Morrison is the author of seven other texts and popular books on space science.

Tobias Owen, Professor of Astronomy at the University of Hawaii, ranks among the world's leading experts on the solar system. Dr. Owen was a member of the Viking scientific team that studied the surface and atmosphere of Mars, and received NASA's medal for exceptional scientific achievement for this work in 1977. He led the group of Voyager scientists that discovered the rings of Jupiter in 1979 and is a member of the scientific teams for the Galileo, Comet-Rendezvous-Asteroid-Flyby, and Cassini-Huygens missions, while studying planets, satellites, and comets with the telescopes on Mauna Kea.