I found a copy of the Liber Lucifer Ordinis Novi, a book which teach spells of the devil! What do you do with it? Do you learn it, sell it? Playing a faithful paladin, I have the idea of destroying it.

But I fear to make a mistake, will I have any use of it? I would have given an experience or an alignment bonus if i were in the dev team! But I'm not. lol

If you learn it, you are always free to just purchase the spells at Novice rank and keep the Infernal magic skill at 1. Among the spells that prefer low alignment to cast successfully, only the spell Shatter in Pagan magic is useful.

Selling it is preferred, none of the merchants in the game seem to care or say anything whenever you sell any items from pagans, monsters or heretics.

If you prefer to destroy it, it is also fine as the book doesn't fetch that good a price anyway.

If you change your mind later on after selling or destroying the book, you can always buy magic boxes from the town alchemist or get from loot, save your game and summon the genie to ask to trade with you. The genie will randomly have one or two spellbooks from any school of magic each time.