Can a magic-user who finds a scroll in a dungeon take said scroll and copy the spell to his/her spell book so that he/she can prepare that spell in the future? Also if the character finds the scroll of a spell he/she already knows can the magic-user use said scroll normally?
When you find a spell scroll, you have two options:
- Scribe the spell into your spellbook (which consumes the scroll), which makes the spell available for you to memorize.
- Cast the spell from the scroll (which consumes the scroll).
So the answer to your question is 'Yes'.
Actually, this depends on if you're playing 1ed or 2ed of AD&D. In 1st ed, you needed to use the Write spell (1st level) in order to transfer the spell into your spell book. You also needed to make certain that you could interpret the spell (look under intelligence) and not exceed the maximum number of spells per level (also based upon intelligence).
2ed doesn't seem to have the Write spell listed, but does have the intelligence check & max number of spells per level.
There is a great article by by Lenard Lakofka in the free publication by &Magazine Issue: #9 – "Spells and Spell Casters" located at: http://www.and-mag.com/2014/05/9-spells-spell-casters/ where Mr. Lakofka covers the Write spell in depth. However, his article expands on the spell, so you need to have the original PHB1 text which Mr. Lokofka does not duplicate. So Enjoy! :)