Book of Secrets

Effect

Randomly adds the effect of Treasure Map, The Compass, or Blue Map for the duration of the current floor.
- (Added in Repentance) If all effects are active, X-Ray Vision is provided for the floor instead.
Repeated activations will continue to add the other items' effects.
- (Removed in Repentance) The chosen effect on activation may be one that Isaac already has - effectively doing nothing.
  - (Added in Repentance) Book of Secrets cannot give mapping effects that Isaac already has (whether from a previous activation or through possessing the equivalent item). After all effects have been given, further activations do nothing.
(Added in Repentance) Reveals rocks with (Crawl Space) Crawl Spaces in a room with one.
(Added in Afterbirth †) This item belongs to the Bookworm set. Collecting three items from this set will transform Isaac into Bookworm.

(Removed in Repentance) Book of Secrets has no effect on floors affected by (Curse of the Lost.png) Curse of the Lost or an Amnesia pill.
- (Added in Repentance) If (Curse of the Lost.png) Curse of the Lost or an Amnesia pill is active on a floor, X-Ray Vision effect is provided immediately.

(Added in Repentance) Book of Virtues: Spawns wisps in the middle ring, looking like tiny spinning question marks. The wisps invoke the effect of Cracked Orb when destroyed.
(Added in Repentance) The Mind: Immediately gives the X-Ray Vision effect for the floor upon use.