Garth Nix is an Australian SF / Fantasy writer for young people whose work has wider appeal. Well read, perhaps a must for a class writer, but he blends whatever influences he has into his own style. Besides a good imagination his work touches some deep chords.
Lirael published in 2001 is the second book in the "Abhorsen" series. This series is set in a world similar to early nineteenth century Europe, but a Europe with a magical 'Berlin Wall'. On one side of the wall no or little magic, the people think of magic as superstition. On the other side demons and revenants and undead reign supreme. The Abhorsens are a line of necromancers who keep order by making sure the dead stay dead, take the final trip to the Ninth Gate. "Lirael" is a book of two halves. In the first half Lirael grows up in the citadel of the Clayr, a people who can foretell the future. But Lirael is on the outside of Clayr society as she does not develop this talent. Instead she becomes a librarian and explores the Library - which is one strange place. In the second half Lirael leaves the Clayr citadel and goes forth on a quest to prevent an ancient evil from returning to the Old Kingdom. The world Nix has created is a fascinating one, magical as it should be. Besides Lirael herself there are complex characters like the Disreputable Dog, and the cat Mogget from "Sabriel". Lirael's story is interwoven with that of other characters as we move towards the final climax iin "Abhorsen".
Mister Monday published in 2003 is the first book of the "Keys of the Kingdom" series. A young boy Arthur finds himself on a quest in the House, a vast other place. He has to recover seven magical keys from seven trustees, each named after a day of the week. To stop Arthur the trustees threaten to destroy the world. "Mister Monday" has Nix's imagination in full flow. We explore the strange House along with Arthur, and discover the strange denizens in it. Nix also finishes the book well. The "Keys of the Kingdom" series is based to some extent on Jewish / Christian beliefs. To some extent. There's the idea in the books of the "Great Architect" who created the House, and left behind a Will (which the seven trustees have split up and hidden.) Originally each of the trustees was going to embody a particular sin from the Seven Deadly Sins. Monday was sloth, as Wednesday was gluttony. By the time we reach "Lord Sunday", the last book, it feels like Nix has slightly run out of steam. But anyone who cites Philip José Farmer and Roger Zelazny as influences is a great writer in my book!