If a Wizard finds the spellbook of the evil Wizard they discovered, how does the process of finding out which spells are in the spellbook work? (Assume the evil Wizard didn’t simply write the spells’ names in common at the top of the pages or create an index.)
- Does the Wizard have to spend 2 hours per spell level “deciphering the unique system of notation” to be able to tell that the spell they’ve been studying is detect magic? Or can they tell at a glance that it’s detect magic before spending the 2 hours?
- Does it require the 50gp per spell level cost just to figure out what the spell is, or do they get to choose whether to spend it after figuring out what spell it is, as part of deciding whether to copy the spell into their spellbook?
From the 5e Basic Rules, Chapter 3, pg. 31 (emphasis mine):
Copying a spell into your spellbook involves reproducing the basic form of the spell, then deciphering the unique system of notation used by the wizard who wrote it. You must practice the spell until you understand the sounds or gestures required, then transcribe it into your spellbook using your own notation. For each level of the spell, the process takes 2 hours and costs 50 gp. The cost represents material components you expend as you experiment with the spell to master it, as well as the fine inks you need to record it.