This is an amazing supplement to the Atlantis: The Second Age rulebook. It feels like a full colour double sized World of Greyhawk for AD&D or Scavenger Sons for Exalted. It is filled with inspiration and plot hooks whilst preserving open spaces to be filled during play.
Between having a vague long term plot idea as GM, the PCs created by my players via the life paths and the relevant sections in Gegraphica, creating sessions of adventures is an absolutely breeze.
This book also contains the Atlantis chapter from the rulebook, so the setting presentation is complete and can be used with another rules system if preferred.