So, I discussed some issues and solutions about learning spells and spellbooks previously here and here. But as the mages in the game have advanced in level (and I’m talking about the actual mages, not the Sorcerer, the Illusionist, or the Diabolist) I’ve looked at how things work and I’m still not exactly happy with things.
I like the difference between grimoires and codices that I proposed, but I also like the idea that mages learn a new spell with each level – or at least that they have a chance to if there are easily available ways to learn a certain number of basic spells. But the rules for spell creation make that somewhat unlikely if we used them, and the chance to learn based on Intelligence seems to be a bit off as well. So, I think a nice compromise would be the base percentage to learn spells off of Intelligence, +5% per experience level, -5% per level of the spell attempted – for common spells only (ala spells from the Players Handbook and Unearthed Arcana). I think it would also be reasonable to say that mages are allowed the opportunity to invent spells instead with the basic percentage from the Dungeon Masters Guide instead of trying to learn a common spell – but learning common spells is much obviously much easier and sure.
So, this provides mages multiple ways to learn spells.
1- The basic texts and codices that hold a number of essentially universal spells. Chance to learn must be rolled, but different codices provide multiple attempts to learn the spell. E.g. if a character doesn’t understand it in the Codex Magica then the Book of Seven provides a new opportunity to learn the spell.
2- The grimoire of other mages – either via purchase, trade, or by way of spoils. Chance to learn must be rolled, and this more “one-shot” in nature unless the mage is unable to learn the minimum number of spells per level.
3- Figuring out common spells as part of the natural process of gaining new levels. If a spell is learned this way, it is automatically known.
4- Inventing spells. Again, these spells are automatically known to the mage.
All of this makes things a bit easier on the put-upon mage when compared to how easy the Clerics, Druids, and Illusionists have it in general. I can exactly say that this is perfect, but it’s a pretty simple and non-kludgy way to handle things.