Unlike settings such as Forgotten Realms or Dragonlance, Ghostwalk was designed to be released as a single book containing all the material for the world.
In the immediate surroundings of the city of Manifest, the ghosts of the dead may cross the barrier into the land of the living, and interact with their loved ones as translucent beings composed of ectoplasm.
The bodies of these ghosts are marked by whatever injuries killed them, and they are often driven by a craving for some aspect of the living world, such as food or music.
Their efforts have caused the city to be razed and rebuilt a myriad number of times, resulting in an underworld of forgotten catacombs surrounding the Veil of Souls which is a common call to adventure in the world.
[2][3] Craig Shackleton for SF Site wrote a fairly positive review of the Ghostwalk sourcebook, complementing its unique twist on the common fantasy conventions, while noting the coming obsolesce of the original 3rd edition system it was written in.