He knows too much and must leave, albeit with a choice of parting gifts. He declines a magic sword and magic harp that would make him the greatest warrior or greatest bard and takes the massive "Book of Three", which "holds everything that was ever known, is known, and will be known".
He knows too much and must leave, even with an assortment of gifts. He declines a magic sword to become the greatest warrior or a magic harp to be the greatest bard and instead takes the voluminous "Book of Three," which encompasses all known knowledge, both past and future.