From the back cover:
The water world of Atlantis has resisted the CEF invaders for more than twenty years, neither side having the resources to break the stalemate. Now new forces are coming into play that threaten the balance as other colonies reach out across the Gateweb to twist the Atlantean conflict to their own ends. Utopia stands with Earth, developing new submersibles and weapons of war, while Terra Nova - who threw back the invaders decades ago - move to support the native resistance. Who will prevail, and can Atlantis afford the cost of either failure or victory?
Atlantis is a deadly waterworld where even the slightest mistake can spell instant death. This sourcebook includes:
A complete history of Atlantis' colonization and its war against the CEF.
Information on the Atlan Corporate Hegemony.
Details of Atlantean Gaianism.
Information on the CEF Fifth Fleet, the Antartis resistance and the Waverider sub-culture.
Full write-ups and maps for 16 Atlantean city-states and Tels.