Type: Summoning
Strategy: Summoning a demon that will go on a rampage, killing all who are not protected from evil, this spell can turn an acceptable situation into a disaster. Since the demon will attack your party and is impossible to control, chaos will ensure. The protection from evil spell will let you cast it safely, but it is still fickle.
Importance: Low
Type: Charm
Strategy: This spell lets you charm the undead. Since the undead are ever-present in Baldur's Gate II, this spell is extremely useful. Otherwise, it acts and works like any other charm spell (for reference, see charm person).
Importance: Moderate
Type: Area damage
Strategy: This spell is much like a fireball, except that this spell can be delayed until triggered. Like skull trap, delayed blast fireball will not cast until someone walks within range and triggers it. When it does, it will do 14d6 damage (with half of that, if successfully saved against), which is very hefty. It works well as a trap, but otherwise, it has the same problems as skull trap.
Importance: Moderate
Type: Touch damage
Strategy: Instantly killing the enemy and doing 2d8+1 damage if your enemy saves, this is a win-win spell. Since it will kill the enemy outright or deal a good amount of damage, it is one of the best damage spells around.
Importance: High
Type: Other
Strategy: This spell will summon your very own genie. When you do, he will tell you that you can pick either a permanent wish or a reoccurring wish. You can choose to heal your party, summon monsters to fight for you, or other such things. Be careful what you wish for, and make sure there is no way for your choice to go wrong. For example, to summon a horde of monsters to overrun your enemy will summon a horde of bunny rabbits. To ask for your party to be healed will heal your party about the equivalent of cure serious wounds spells. You can wish for magic items and get a variety of things, most being good. Your wisdom will play a large part in the results of this spell.
Importance: High
Type: Defense
Strategy: Much like protection from magical weapons, this spell will shield you from weapon damage. In this case, any weapon +2 or lower will be ineffective. However, it also inherits from protection from magical weapons the duration of four rounds. So, it is, again, mostly useless.
Importance: Low
Type: Imbuement
Strategy: This spell is exactly like improved invisibility, but works on the whole group. It has same pros and cons, strategies, and uses.
Importance: Moderate
Type: Summoning
Strategy: Summoning a floating sword (+4) that acts as a fighter equivalent to half the level of the caster, this spell acts much like an elemental. Being only equivalent to half the level of the caster, though, the sword will have rather low hit points and a somewhat difficult time hitting its target. Overall, this spell is an acceptable summon, usable in the same ways described for monster summoning I.
Importance: Moderate
Type: Hindrance
Strategy: Much like power word: silence, this spell casts stun with no saving throw. However, an added plus is that the more hit points the target has, the longer it will be stunned. The stun works the same way as a regular stun. This is an absolute must for later levels, especially boss battles.
Importance: High
Type: Missile damage
Strategy: Working as an upgraded color spray, this spell has the same strengths and weaknesses as its cousin. The only difference is that this does more damage and has more special abilities. Still, it is difficult to use and often hurts party members. Much less risky damage spells are available, but it can pack a punch.
Importance: Moderate