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. You can only get one per character upon mission completion but you can trade for more.

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

Collectors
Keeper of Shadows 15^50, zealous, +30hp 15^50, zealous, +30hp 15^50, zealous, +30hp
 * Talons of the Forgotten (req. 9 dagger mastery) slashing damage
 * Ungues of the Forgotten (req. 9 dagger mastery) slashing damage
 * Split Chakrams of the Forgotten (req. 9 dagger mastery)

Keeper of Steel 15^50, sundering 20/20, +30hp 15^50, sundering 20/20, +30hp 15^50, sundering 20/20, +30hp
 * Forgotten Axe (req. 9 axe mastery) slashing damage
 * Forgotten Hammer (req. 9 hammer mastery) blunt damage
 * Forgotten Sword (req. 9 sword mastery) slashing damage
 * Forgotten Shield (req. 9 tactics) +10vs cold damage
 * Forgotten Shield (req. 9 strength) +10vs earth damage

Keeper of Elements All are: +15 energy, halve skill recharge 20%, energy +5^50, +30hp
 * Staff of the Forgotten (req. 9 air magic) lightning damage
 * Staff of the Forgotten (req. 9 earth magic) earth damage
 * Staff of the Forgotten (req. 9 fire magic) fire damage
 * Staff of the Forgotten (req. 9 cold magic) cold damage

All are: halve skill recharge 20%, energy +5^50
 * Golden Boar Scepter (req. 9 air magic) lightning damage
 * Golden Boar Scepter (req. 9 earth magic) earth damage
 * Golden Boar Scepter (req. 9 fire magic) fire damage
 * Golden Boar Scepter (req. 9 cold magic) cold damage

Keeper of Nature 15^50, zealous, +30hp 15^50, vampiric, +30hp 15^50, sundering 20/20, +30hp 15^50, cripp +33%, +30hp 15^50, bleed +33%, +30hp
 * Forgotten Flatbow (req. 9 marksmanship) piercing damage
 * Forgotten Hornbow (req. 9 marksmanship) piercing damage
 * Forgotten Longbow (req. 9 marksmanship) piercing damage
 * Forgotten Recurve Bow (req. 9 marksmanship) piercing damage
 * Forgotten Shortbow (req. 9 marksmanship) piercing damage

Keeper of Light All are: +15 energy, halve skill recharge 20%, energy +5^50, +30hp
 * Staff of the Forgotten (req. 9 divine favour) fire damage
 * Staff of the Forgotten (req. 9 healing prayers) light damage
 * Staff of the Forgotten (req. 9 protection prayers) light damage
 * Staff of the Forgotten (req. 9 smiting) light damage

All are: halve skill recharge 20%, energy +5^50
 * Golden Boar Scepter (req. 9 divine favour) fire damage
 * Golden Boar Scepter (req. 9 healing prayers) light damage
 * Golden Boar Scepter (req. 9 protection prayers) light damage
 * Golden Boar Scepter (req. 9 smiting) light damage

Keeper of Bone same as other caster items blood magic and soul reaping do dark damage curses and death magic do cold damage

Keeper of Spirits same as other caster items communing and restoration do dark damage spawning powers and channeling do light damage

Keeper of Illusion same as other caster items all do chaos damage

Keeper of the Scythe 15^50, zealous, hp+30 15^50, sundering, hp+30 15^50, vampiric, hp+30
 * Eyes of the Forgotten (req. 9 scythe mastery) slashing damage
 * Hand of the Forgotten (req. 9 scythe mastery) slashing damage
 * Claw of the Forgotten (req. 9 scythe mastery) slashing damage

Keeper of the Spear 15^50, sundering, hp+30 energy +5, furious, hp+30 (i think) energy +5, enchantment 20% longer (don't remember the other mod?)
 * Courage of the Forgotten (req. 9 spear mastery) piercing damage
 * Prayer of the Forgotten (req. 9 spear mastery) piercing damage
 * Spirit of the Forgotten (req. 9 spear mastery) piercing damage