The Abhorsen Series by Garth Nix

From chapters.ca:
Since childhood, Sabriel has lived outside the walls of the Old Kingdom, away from the power of Free Magic, and away from the Dead who refuse to stay dead. But now her father, the Mage Abhorson, is missing, and Sabriel must cross into that world to find him. With Mogget, whose feline form hides a powerful, perhaps malevolent spirit, and Touchstone, a young Charter Mage, Sabriel travels deep into the Old Kingdom. There she confronts an evil that threatens much more than her life and comes face to face with her own hidden destiny.

Lirael has never felt like a true daughter of the Clayr. Abandoned by her mother, ignorant of her father’s identity, Lirael resembles no one else in her large extended family living in the Clayr’s Glacier. She doesn’t even have the Sight -- the ability to See into the present and possible futures -- that is the very birthright of the Clayr. Nonetheless, it is Lirael in whose hands the fate of the Old Kingdom lies. She must undertake a desperate mission under the growing shadow of an ancient evil -- one that opposes the Royal Family, blocks the Sight of the Clay; and threatens to break the very boundary between Life and Death itself. With only her faithful companion, the Disreputable Dog, to help her, Lirael must find the courage to seek her own hidden destiny.

I can't really describe the third book without giving away parts of the first two.