His latest series is Keys to the Kingdom, a seven-part series. Seven days. Seven keys. Seven virtues. Seven sins. One mysterious house is the doorway to a very mysterious world — where one boy is about to venture and unlock a number of fantastical secrets. Mister Monday launched the series and won the Aurealis Award for Best Children's Novel. Arthur Penhaligon suffers a near-fatal asthma attack, but it is a key shaped like the minute hand of a clock that saves him. When a stranger named Mister Monday stops at nothing to retrieve the key, Arthur ventures into a house that contains an entire world and only he can see. It is where he must unravel the secrets of the key. In the second installment, Grim Tuesday, Arthur meets a new enemy who threatens both Arthur's family and his well-being. Drowned Wednesday is the third book as well as the name of the enemy who draws Arthur even deeper into the mystery of the House.

After receiving his degree in professional writing from the University of Canberra, he started working in the publishing industry, steadily moving from the positions of sales rep to publicist. In 1991 he became a senior editor with a major multinational publisher. After a period in Europe, the Middle East, and Asia in 1993, he left publishing to work as a marketing communications consultant. In 1999, he reentered the publishing world to become a part-time literary agent.

Garth Nix currently lives in Sydney with his family and lots of books.