Spells are never merely ‘cast’ from a ‘list’ of options available to the wizard. A wizard undergoes intense mental duress in merely learning and forming the spells in his minds.
In this game, a wizard can benefit from perusing a spellbook, but in order to benefit from the work, he must truly make the spells his own.
Thus, spell knowledge is distinguished from the merely ability to read a spell. The latter simply implies that you understand what a spell is intended to do, not that you could do it (yet).
The gods of magic have put various limitations on the powers of arcane magic users. First, there is a chance for the effect to be avoided or diminished by the nature of the targets. Some spells have to be aimed effectively to strike their target, and despite their great power, can miss. Other spells have great power but cannot impact certain types of creatures as well. In the first case, the targets get a save to avoid the full effect of the spell. In the second case, spells have to be cast and then an attack roll is made to successfully hit the targets. In the third case, a maximum hit dice or spell resistance prevent a spell from functioning. All of these limitations can be (to a certain extent) overcome by persistent study and growing in experience and power with respect to your magic.
Each arcane power is of a minimum ‘level’ that determines the base level or power a creature must possess before he can learn that spell. You can ‘memorize’ spells, and this enables you to get a discount on the number of arcane spell points it will cost you when you decide to cast the spell. However, it also limits the number of options you have by preventing you from using those spell points in other ways. There are three tiers of spell costs per spell level.
Arcane Costs per Tier
First Tier = Spell Level
Second Tier = Spell Level x 2
Third Tier = Spell Level x 3
At the start of the game, when a wizard begins to cast spells, the first spell you memorize at any level is automatically 1st tier costs. The second spell at any spell level is memorized for the 2nd tier costs. The third spell and any additional spells memorized at a given level is going to be 3rd tier costs. This makes it difficult to use the same spell or spell level an extensive number of times to day.
Due to the chaotic forces that have wracked Krynn over the last few years, magic is coming more readily to mages even at a lower level. The ability to cast a spell spontaneously without preparation is simply equal to the third tier costs. This can be greatly impacted by the waxing and waning of Krynn’s moons, which are gods of magic that impact arcane spells.
Metamagic, Hypermagic, and Paramagic
Mages can learn three types of feats that generally impact the way their spells work.
The first type is metamagic, which effectively increases the spell level. Although metamagic doesn’t impact the arcane magic point costs per spell in any other specific way, metamagic obviously increases the amps required for a spell, because that number is proportional to the spell level.
Hypermagic presents options that push a spell beyond its normal limits with a special arcane magic point cost. You learn hypermagic as you increase your focus on certain spells. Since hypermagic generally increases the amp cost by a factor of the base cost, you generally want them to be your first tier memorized spells.
Paramagic is a way to use your reservoir of arcane magic points to generate spell-like abilities, not unlike the ‘reserve’ feats of 3.5 (complete mage). These feats will enable you to use powers based on spells you have chosen to memorize but have not yet cast, for a minimal cost.
Caster Level and Spell Resistance
The potency of spells increases by regular increments relative to your caster level. Your caster level, in turn, increases when you gain the feat ‘arcane spell casting’. For most characters, this would have to be a general feat, but wizards gains this every time they take a new level of wizard. Your caster level impacts the quality of your spells with respect to spell resistance as well. Creatures with strong resistance to magic can be overcome by powerful and experienced magic users. This is a percent check involving caster level, luck, and your casting attribute (intelligence for memorized spells and charisma for spontaneous spells).