Chronomancers are the travel experts of the magic users. Before becoming one, a magic user must master all the spells of any three mage classes. And once you become a Chronomancer, you lose the power to use all the spells you previously learned. It may sound unfair, but the Chronomancer needs to focus all of his or her attention on the important dimension teleport spells. Don't think you can get around without this spellcaster, because you just can't.
For a list of Chronomancer spells and their effects, visit BT3 Spellbooks