From publisher blurb:
Welcome to the fourth installment of the Advancing with Class series. This supplement focuses on the Magus.
What happens when you combine a Magus with a Summoner? A lot of summoned warriors at your beck and call and the ability to evolve yourself. This supplement offers two hybrid classes based on the Magus, Thirteen Magus archetypes, sixteen new Magus Arcana, and nineteen new spells tailored for the Magus.
So whether you are looking for a whole new way to build a Magus or simply a means to give him a unique flavor, this supplement offers it all.