| spellbook of + detect monsters 
| |
|---|---|
| Appearance | random |
| Spell type | divination |
| Level | 1 |
| Turns to read | 1 |
| Power cost | 5 Pw |
| Ink to write | 5–9 |
| Cost | 100 zm |
| Weight | 50 |
A spellbook of detect monsters teaches the detect monsters divination spell, which reveals the location and identity of all monsters in the level.
At unskilled or basic skill level, the spell functions as an uncursed potion of monster detection, displaying the monsters of that dungeon level against a black background with no map detail. At skilled or expert level it functions as a blessed potion, revealing monsters on the map for 21–60 (more) turns.
Strategy[]
As a level 1 divination spell, detect monsters is useful for training the divination skill, which contains several of the game's most useful non-combat spells. At low skill levels it is probably not as useful as the light spell, especially if you already have intrinsic telepathy from a floating eye.
At skilled or higher it becomes quite useful in its own right, serving as a superior alternative to blind or extrinsic telepathy. Unlike telepathy, monster detection can reveal brainless monsters.