ToME WikiBitsySpider: In short, just spellbooks with a random set of 2-4 spells in them, would drop as "good" items or better.
The spells wouldn't necessarily be related in any way, they'd just be completely random. The books could be named from a file the same way randarts are, and would have the usual chance of being indestructible/fireproof. It might be good to have "lesser" books which can only include spells on the "build your own book" quest list and more powerful ones that can include any spell.
Alternatively, or additionally, more books of preset groups of spells (a la Beginner Cantrips, Teleportation) would be nice: Such as books that include lists of bonus spells from prayer skill (and a god spell for those gods that give very few spells):
===Acolyte Books===
Acolyte's Book of Eru
- Manathrust
- Sense Hidden
- Sense Monsters
- Identify
- Charm
Acolyte's Book of Manwe
- Noxious Cloud
- Invisibility
- Disarm
- Teleportation
- Recharge
Acolyte's Book of Yavanna
- Stone Skin
- Dig
- Grow Trees
- Healing
- Ent's Potion
Acolyte's Book of Tulkas
- Stone Skin
- Dig
- Divine Aim
Acolyte's Book of Melkor
- Charm
- Confuse
- Drain
- Curse
===More books of "similar" spells:===
Book of Building
- Dig
- Stone Prison
- Grow Trees
- Disarm
- Reveal Ways
Book of the Mystic Thief
- Invisibility
- Teleportation
- Disarm
- Charm
- Sense Hidden
Bigby's Handy Book
- Globe of Light
- Ent's Potion
- Dig
- Recall
- Sense Hidden
Kalek's Grimoire of Power
- Vision
- Tracker
- Greater Identify
- Inertia Control
- Probability Travel
Raul's Tome of Destruction
- Fireflash
- Manathrust
- Thunderstorm
- Tidal Wave
- Strike
Tensor's Transformations
- Stone Skin
- Essence of Speed
- Elemental Shield
- Ent's Potion