So I have this character idea: a rogue who wanted to be a wizard, but didn't have enough money to go to a wizard school. And I was thinking, if he stole a wizard's spellbook, what could he do with it? Could he practice the first-level wizard spells during downtime until he memorized them? Or pay someone to copy the spells into scrolls or wands? Or could a wizard teach me a cantrip?
In other words: Do you have to be a wizard to learn spells from a spellbook?
Part of what I was asking was in cases such as when the DM says our characters have some down time in a city; could I use the rules for gaining new proficiencies, languages etc. during downtime to learn a spell from the book? There are phases in the PHB that indicate that spellcasters can make new spells during down time, so it makes sense that a noncaster could learn a spell during down time as well.
(P.S.: This is purely for roleplay, not for any mechanical advantage.)