43 books • 5 series
Voyages to the Planets (Non-Infotrac Version with 2001 Update and Thesky Student CD-ROM)
Voyages to the Stars and Galaxies (Non-Infotrac Version with 2001 Update and Thesky Student CD-ROM)
Voyages to the Stars and Galaxies (with 2001 Update, Thesky Student CD-ROM, and Infotrac)