I was seeing in one of the other threads someone (gut) pointing out that there are many battles in ADOM that are rather... unfair to people who haven't been spoiled a bit. Examples being banshee, gorgons, anything that casts death rays--things that can kill you before you realise you can protect yourself. Rather than trying to address all of these at once, I thought maybe an item would help:

Scroll of monster detection.
When cursed, adds the full description of one random monster into the monster memory, including all special abilities, average stats (at the PC's current DL), speed, etc.
When uncursed, adds the full description of all monsters adjacent to the PC into the monster memory, including special abilities, etc.
When blessed, adds the full description of all monsters on the level into the monster memory.

This would be a very useful item for new players. If you are in a dangerous area, you can read the scroll, then figure out the abilities of all the monsters you come across, and might help you avoid getting into trouble with the odd monster with a new and remarkable power. Might also be useful given that there are going to be many new boss monsters added that might have unusual combinations of abilities.

I would set them at a fairly low danger level, and relatively common--maybe as common as, say, scrolls of uncursing.

An alternate method might be to have it as a book, say a "Monster Compendium". In this case, you type in the name of the monster you want to look up, and it adds that specific monster to the monster memory. The book only has a limited number of reads, however, and then disappears.