ĭavid 'Zeb' Cook developed Planescape when he was assigned to create 'a complete campaign world (not just a place to visit), survivable by low-level characters, as compatible with the old Manual of the Planes as possible, filled with a feeling of vastness without overwhelming the referee, distinct from all other TSR campaigns, free of the words 'demon' and 'devil' and explainable to Marketing in 25 words or less'. However, fan demand for a 2nd Edition Manual of the Planes was strong enough to justify its expansion into a full-fledged campaign setting, and so in 1994 Planescape was released.
When Advanced Dungeons & Dragons 2nd edition was published, a decision was made not to include angelic or demonic creatures, and so the cosmology was largely ignored.
Planescape is an expansion of ideas presented in the Advanced Dungeons & Dragons Dungeon Master's Guide (First Edition) and the original Manual of the Planes.
