Book of Secrets

The Book of Secrets is a Quest Item obtained from the Keeper of Secrets in the Throne of Secrets area, after completing Abaddon's Gate, the final mission of the Nightfall campaign.

Take it to one of the Keepers behind the Keeper of Secrets (Keeper of Scythes, Bows etc) to swap it for a green weapon/item of your choice.

Collectors

 * Keeper of Scythes
 * Keeper of Bows
 * more to be added