- Randomly roll for four additional spells, per the creative variants in my previous post;
- Let the player make up spells she'd like to have and say "those are in the spellbook";
- Just add some spells from other published sources, like maybe some modified druid or cleric spells.
Whichever choice I make, this means the player will eventually do spell research... which means I need to know how a captured spellbook affects spell research. Originally, I was going to just convert the spellbook into a sale value and use that to offset research costs. I figured the sale value of a spellbook is half the cost of replacing a spellbook: 1,000 gp for a 1st level spellbook, double that for each level above the first. But now I think this should only apply to spells that *aren't* in the spellbook. Spells in the spellbook should be easier to research, so I'd say that a spellbook with an unknown spell in it halves the research costs to learn that particular spell. That doesn't really affect M-Us who spend the minimum amount to research a spell, but those who spend more have much better odds: a 5th level M-U researching Fireball who spends 12,000 gp has the following odds of success:
- 30% by default;
- 40% with a captured spellbook that does not contain Fireball;
- 60% with a captured spellbook that contains Fireball.