Spelljammer is a campaign setting originally published for the Advanced Dungeons & Dragons (2nd edition) role-playing game, which features a fantastic (as opposed to scientific) outer space environment. Subsequent editions have included Spelljammer content; a Dungeons & Dragons 5th edition setting update released on August 16, 2022. Spelljammer introduced into the AD&D universe a comprehensive system of fantasy astrophysics, including the Ptolemaic concept of crystal spheres. Crystal spheres may contain multiple worlds and are navigable using ships equipped with "spelljamming helms". Ships powered by spelljamming helms are capable of flying into not only the sky but into space. With their own fields of gravity and atmosphere, the ships have open decks and tend not to resemble the spaceships of science fiction, but instead look more like galleons, animals, birds, fish or even more wildly fantastic shapes. The Spelljammer setting is designed to allow the usual sword and sorcery adventures of Dungeons & Dragons to take place within the framework of outer space tropes. Flying ships travel through the vast expanses of interplanetary space, visiting moons and planets and other stellar objects. Like the Planescape setting, Spelljammer unifies most of the other AD&D settings and provides a canonical method for allowing characters from one setting (such as Dragonlance) to travel to another (such as the Forgotten Realms). However, unlike Planescape, it keeps all of the action on the Prime Material Plane and uses the crystal spheres, and the "phlogiston" between them, to form natural barriers between otherwise incompatible settings. Though the cosmology is derived largely from the Ptolemaic system of astronomy, many of the ideas owe much to the works of Jules Verne and his contemporaries, and to related games and fiction with a steampunk or planetary romance flavor. A strong Age of Sail flavor is also present. Publication history Shannon Appelcline, in the book Designers & Dragons (2011), highlighted that in 1989 Spelljammer was the first of a host of new campaign settings published by TSR. It was created by Jeff Grubb and "introduced a universe of magical starships traversing the ‘crystal spheres’ that contained all the earthbound AD&D campaign worlds. It suggested a method to connect together all of TSR's settings and at the same time introduced fun new Jules Verne-esque technology that had never before been seen in the game. It was innovative and popular." Appelcline commented that Spelljammer "offered a way to connect every single D&D fantasy