Continuing on the theme of divination, and GURPS Dungeon Fantasy as well, what divination spells do I think as especially well-suited to DF?
Here I'm using Divination as a means of getting the GM to give you hints. Direct detection spells should just be assumed to be useful.
The spells I find the most useful are the ones that are relatively simple to cast, don't require very special conditions, and aren't subject-specific. Here is a look at all of them.
From GURPS Magic, page 108-109:
Augury - potentially useful, especially outdoors. In a dungeon, it's much trickier - you'll need to be reading the scattering of rats or the patterns of slime on the ceiling. It's an easy spell to learn - History and one spell from each of the four elements.
Cartomancy - the -5 for divining things that aren't about people makes this less useful. Especially if monsters aren't people.
Crystal-Gazing - solid choice. It's -10 for using water, but you can carry a mirror. Easy prereqs.
Dactylomancy - five word limit is tough. Not every useful.
Extispicy - One question per animal, minimum 20 pounds. Only handy once you've slain monsters the GM considers appropriate. Works best on life-or-death, which isn't a great way to find out hints on puzzles.
Gastromancy - Cool, but it's 5 FP to the subject and needs Hypnotism, a skill most won't really have or use if they do.
Geomancy - useful outdoors, moderately useful overall. Worth considering if you have Earth spells anyway.
Lecanomancy - The flat -5 sucks, but the halving of time penalties is useful. Tricky to carry water and stuff to toss into it.
Numerology - basically useless in a DF game.
Oneiromancy - tough to actually get to cast this - requirement for sleep, a lucky roll on dreaming, etc.
Physiognomy - only useful on the subject, which can be useful but frankly Death Vision will do the job more effectively for less investment in time and cost.
Pyromancy - useful if you have something of the subject to burn, otherwise the -4 hurts. Still, fire wizards will want this.
Sortilege - useful.
Symbol-casting - useful, especially if "true tokens" exist for the +2. Half the time of most other divination spells!