world, was thus one of the first true crossovers" in role-playing games. Advanced Dungeons & Dragons (2nd edition) The Spelljammer: AD&D Adventures in Space space fantasy boxed set was released in 1989. Several of TSR's other campaign worlds had their own sections in the Spelljammer Boxed Set - Realmspace for the Forgotten Realms, Krynnspace for Dragonlance, and Greyspace for Greyhawk. Along with the new sphere - Clusterspace - they were known as the "Big Three and Astromundi". Dark Sun, Ravenloft and Mystara weren't included, as the first two did not fit with the setting and the Mystara only used the D&D rules, not the AD&D rules. The product line would be expanded with a number of boxed sets and accessories such as Lost Ships (1990), Realmspace (1991) and The Astromundi Cluster (1993). Appelcline commented that The Astromundi Cluster acted as "a soft reboot of the Spelljammer line" and was more of setting focused sourcebook than previous Spelljammer books which acted more "as a conduit between all of the other AD&D settings". The first adventure module, titled Wildspace, was released in 1990; four connected adventure modules followed it. A longer campaign module, Heart of the Enemy, was then published in 1992 followed by an adventure anthology, Space Lairs, in 1993. In 1993, Space Lairs and The Astromundi Cluster were the final products of the line. Appelcline commented on the end of the setting in the Advanced Dungeons & Dragons era: "TSR’s fifth second-edition campaign world, Planescape (1993), was released to replace Spelljammer, which had just then ended. TSR wanted a new world-spanning setting and Slade Henson came up with the answer by suggesting a new setting built on Jeff Grubb's first-edition Manual of the Planes (1987). [...] Unlike Spelljammer this new setting had a strong geographical centre, the City of Sigil, resolving a flaw in the Spelljammer setting that denied players a good home base." Dungeons & Dragons (3rd edition) The Spelljammer line of products was discontinued by TSR before they were acquired by Wizards of the Coast in 1997. In May 2002, Paizo published an article for Spelljammer in Dungeon #92 titled "Spelljammer: Shadow of the Spider Moon". Using the D20 system, it provided new rules for firearms and spelljamming, as well as skills, feats and prestige classes. Spelljammer monsters such as neogi and giff were not used. Instead, it featured creatures from the Monster Manual such as drow, formians