Sigil, the City of Doors, located high above the Outlands, is run by different factions, and which contains portals that connect to every plane and layer.
Depending upon the parameters of the campaign, players may choose from the standard AD&D game archetypes, including humans, dwarves, and halflings, or opt for planar races, such as bariaur, githzerai, and tieflings.
The first division, the Prime Material Plane, includes the worlds associated with the Dragonlance, Ravenloft, and Forgotten Realms settings.
[2] Sigil is centered in the Outlands, a stable area also known as Concordant Opposition, and contains doorways leading to every locale in the multiverse.
As described in the 96-page "Sigil and Beyond" book, it resembles a medieval city "built on the inside of a tire that hovers over the top of a gods-know-how-tall spike, which rises from a universe shaped like a giant pancake."
[2] Editing was by David Wise, the conceptual artist was Dana Knutson, illustrations were by Tony DiTerlizzi, graphic design was by Dee Barnett and Dawn Murin, and the cover was by Robh Ruppel.
[2] Planescape Campaign Setting won the Origins Award for Best Graphic Presentation of a Roleplaying Game, Adventure, or Supplement of 1994.
He said that Planescape "is a superb addition to the AD&D multiverse [...] it's clear that a great deal of thought and effort has gone into this product.
The writing is clear, most topics are covered in detail and adventure ideas are either presented directly or dropped in as 'seeds' for you to pick up on.
"[1] Alloway praised Cook's efforts to make the planes accessible and enjoyable for lower-level characters, and for developing an important part of the AD&D multiverse, and he appreciated the setting's emphasis on roleplaying and critical thinking rather than moving and hacking.
He complimented the set's distinctive graphic looks, from "the weathered-metal texture of the book covers to the bizarre headline typeface to the odd squiggles of brown and blue that are on nearly every page".
[2] He declared that the original Manual of the Planes "stands among the best role-playing supplements of the 1980s" but "never really caught fire", speculating lack of interest, uncertainty by game designers of how to further support it, or confused players; Swan said that the book had in a sense been "reincarnated as the Planescape setting, a spectacular boxed set and TSR's most ambitious campaign world to date.
"[2] Swan also felt that "Cook insists that the mechanics serve the story, not vice versa, making this an extremely user-friendly multiverse.
"[2] Commenting on the set's geography, Swan said "With energetic, vividly imagined descriptions, Cook captures the magnitude of the multiverse and the diversity of its inhabitants.
[2] He called "The Rules of Threes" the "most compelling" of the setting's innovations: "it's a design philosophy that characterizes every element of the game as one third of a whole.
Traditional AD&D game campaigns can be considered as sets of opposites: good and evil, night and day, up and down.
The Planescape setting adds the intermediary: good, evil, and neutrality; night, day, and twilight; up, down, and sideways.
[2] In 2013, Alex Lucard, for Diehard GameFAN, highlighted the Planescape Campaign Setting on a list of 2nd Edition products he would want rereleased on DNDClassics.