Groundlings have no idea, but any spelljamming adventurer worth his salt knows the universe is huge! Let Practical Planetology open new possibilites for your AD&D SPELLJAMMER campaign. Herein find fifteen unique planets, exotic and mysterious, ripe for plunder or other less profitable adventures. Weigh anchor at the air world Alabeth, and float with marooned elves atop their massive holbags. Visit the mithril dragons of Radole who ride the hot thermals over lakes of molten tin. Endure the searing flames of the efreeti city on Ignia, ow swim among the island necrocracies - nations of undead from a destroyed planet - on Charon. These and other bizarre worlds of adventure await you in Practical Planetology, along with beasts native to them, eleven new monsters in all. All you'll need is a ship, a helm, and a star to steer them by! Practical Planetology contains material suitable for characters of any level.