Spell memorisation

Spell memorisation is the process by which you learn spells from spellbooks in your inventory. This can be done by clicking on the spellbook, viewing the Memorisation tab of your inventory screen, or pressing M and selecting the desired spell from the list.

Memorisation restrictions

While any character may gain access to spells, the following restrictions apply:

• You can memorise at most 20 spells. A scroll of amnesia or Sif Muna's Forget Spell At Will ability will allow you to forget unwanted spells to free up space.
• Each spell has a spell level, ranging from 1 to 9. You can only memorize a total of (Experience Level + (2*Spellcasting)) levels of spells. The one exception to this is the pair of spells Fireball (level 6) and Delayed Fireball (level 7). Knowing both uses up only 7 levels.
• Trying to memorise a spell with the Blurry Vision mutation has a 25% chance of failure per level of mutation.
• You can't memorise while confused or berserk.
• You can't memorise a spell whose level is higher than your experience level.
• In addition, some species cannot learn certain spells:
  • Deep Dwarf: Regeneration
  • Felid: Fire Brand, Freezing Aura, Lethal Infusion, Warp Weapon, Excruciating Wounds, Poison Weapon, Portal Projectile, Sure Blade, Tukima's Dance
  • Ghoul: Blade Hands, Borgnjor's Revivification, Cure Poison, Death's Door, Dragon Form, Ice Form, Necromutation, Spider Form, Statue Form, Stoneskin
  • Mummy: Same as ghouls, plus Alistair's Intoxication, Passwall, Regeneration, Summon Horrible Things.
  • Vampire: Borgnjor's Revivification, Death's Door, and Necromutation.
  • Lich Form: Same as mummies. If they knew the restricted spells before casting Necromutation, they are unable to cast them in lich form, with the exception of Necromutation itself. Note that you can't rememorize Necromutation in lich form.

Memorisation success

Your chance of success at memorising a spell is related to your chance to cast the same spell (calculation is not exactly the same, but close). You can guess the chance you have to memorise a spell by looking at the warning message you get:

Warning message	Chance of success
This spell is very difficult to memorise	<15%
This spell is quite difficult to memorise	15–48%
This spell is rather difficult to memorise	48–75%
This spell is somewhat difficult to memorise	75–92%
This spell is not that difficult to memorise	>92%

"Difficult" may be replaced by "tricky" or "challenging"; "memorise" may be replaced by "commit to memory", "learn", or "absorb". These changes are only flavour.

Failing to memorise a spell has no effect, except from a Book of Annihilations, a Book of Demonology or a Necronomicon. In these cases, you'll suffer a (likely high level) miscast effect from Conjurations, Summonings or Necromancy, respectively.

History

In 0.12 spell memorization failure will be made binary: all of the reasons given above for not being able to memorize a spell will remain true, but the difficulty-based random chance to memorize a spell will be removed. Instead, any spell with a nonzero success rate can be memorized, although the game will warn you if casting the spell carries a significant risk of nasty miscast.