Noted author and co-creator of the Forgotten Realms setting has crafted a new world for D&D/D20 players to experience. Although not as geographically expansive as FR, Castlemourn is every bit as ambitious and somewhat easier to digest. The setting is semi-closed using a land roughly 1200 miles wide and 300 miles deep isolated by mountains, seas, and remnant magicks left over from when the land itself revolted gainst the ills mankind and their peers had inflicted upon it some three hundred years before. No passes or sea lanes exist to allow transit to and from Castlemourn but some may enter the lands through "estemal" - planar or dimensional portals from other worlds that can be used to introduce subject matter from outside Castlemourn. Questors seek out artifacts and knowledge about life before the cataclysm giving players an unusual stamp of legitimacy in their activities. New classes, magic, and races are introduced including the mysterious Thaele. Astrological signs also impact on the game in a unique twist that adds to character flavor. Castlemourn is also replete with setting calendars, directions, measurements, coinage names, dietary details and other information designed to enhance immersion.

I really enjoyed the setting. It is quite detailed without being overly burdensome and the relatively limited land mass makes it somewhat easier to do justice to the whole product. The “estemal” give DMs considerable latitude to use external material without undermining the basic foundation of the setting. If there is a problem to the setting, it is because it was released so close to the debut of the D20 4th edition rules that one has to wonder about any future material for the setting being released.