|When a Mage reads a scroll (click on the scroll in his inventory),
the "Write Magic" option will be offered if the Mage has room in his spell
book and does not already have that spell written into the book.
Clicking on "Write Magic" will attempt to learn (write to spellbook) the
spell based on the Mage's "% to Learn" ('Mild Cheat' - save prior to attempting
to learn a spell as it may fail).
The maximum spells/level that a Mage can write into his spell book is
determined by his Intelligence (see "Max Spells/Level" column, table 1
on page 136 of the game manual) as is the highest level of spells a mage
can learn ("Spell Level" column in same table).
Scrolls can be found in various places, recovered off the bodies of
vanquished enemies, purchased in stores/shops, received as quest rewards,
and 'lifted' from the pockets of unsuspecting npc's (if your thief is good