Katherine Kurtz' Deryni books are definitely "rule based" magic as they rely on specific actions and word forms for a result. You also have to be born with the talent.

Where would you class psionics / science masquerading as magic.
Andre Norton's Crystal Gryphon for example?

Diane Wynne Jones' Chrestomanci series is another "rule based" magic system but also borders on wondrous at times.

Harry Dresden's Magic follows rules too.


The rule of thumb for me tends to be there are magic systems that rely on a mnemonic that key the practitioner's magic. Whether it is words, gestures or both.

Then there is the magic system where the "thought is the deed" and the magic happens after an effort of will.

It also helps to consider where the "power" comes from, is it from within or without? That is where does the energy stem from?

Is the spellcaster exhausted because they draw all the energy from their own resources? A lot of psionic based systems tend to do this.

Or does the magus draw the energy from the world around, ie does it go cold etc.

Do they drain it from living things? - Damn can't remember which author had magicians and their "sources" people who provide the energy for the spell/ magic.