Sabriel by Garth Nix
After finishing school in Northern Ancelstierre, Sabriel must leave the life she's known behind and enter the Old Kingdom to search for her missing father. The Old Kingdom may be the place of her birth, but it's strange and full of dangerous magic, and of course, the Dead. Charter magic-trained she may be, but Sabriel is unprepared for the trials that face a budding Abhorsen. Chased by powerful Dead creatures and armed only with the bells of a necromancer and the advice of a Free Magic cat, Sabriel journeys north to find her father and the source of a terrible new power that threatens Life.
Sabriel is the first book in the Abhorsen series by Garth Nix. It's high fantasy at its best, in my opinion. I always find myself immediately drawn into the enthralling world of Charter Magic, Free Magic, and Necromancy, unable to put the books down until I've finished the series (usually in a single weekend).
View my suggested books by Garth Nix