The White and the Red

From the introduction:

Powers of the White are granted instantly with no skill roll, and generally ask little in return (aside from the drain of Magic points). The magic of the Red is quite different. A Sorcery check is needed to invoke the magic (along with materials, words of power, or anything else required). A failed check (usually) produced no result. A successful check yields the spell, at least in accordance with the caster’s ability.

User summary:

A sourcebook of magic.