From the back cover:
"Unlock the Key to Your Destiny!
The Codex of the Immortals provides players with the tools they need to further develop their characters for The Everlasting Role Playing Game. Inside these pages you will find information about what it means to be one of The Everlasting. You will find guidelines to help develop rich and exciting backgrounds for your protagonists as they move their characters through the Legendmaking experience. Learn more about the history of The Secret World: About the Fall of the Dragons, the rise of the merodachs and the Azhi Dehaka, about The Death Knell and the coming of the daimons and more!
The Codex of the Immortals is a source book for The Everlasting Role Playing Game. It is fully compatible with any of the four stand alone foundation books. Inside you will find information on how to further develop your protagonists including guidelines on fellowships, mentors, apprentices, honor duels and dominions. The Codex has over hundred descriptions for you to use to further define and mold your characters. Guidelines on creating custom powers are also included to allow you to unleash the full power of your protagonists."