Start with Sabriel. It is the first Old Kingdom book published, it is self-contained enough to work as a standalone, and it teaches you the magic system — the Charter, Free Magic, the seven bells and the nine gates of Death — by walking a competent teenager through it rather than by explaining it.
The obvious alternative is Clariel, which is set roughly six hundred years earlier and therefore comes first on any chronological list. Do not start there. It assumes you already understand the Abhorsen line and the Clayr, it is deliberately the bleakest book in the sequence, and its protagonist is a study in someone going wrong. As a first Nix it is misleading; read after Abhorsen it is devastating in the way it was built to be.
The Old Kingdom, in publication order
Sabriel, then Lirael, then Abhorsen. Note that the middle and third books are effectively one novel split in two: Lirael ends mid-story on a cliffhanger, so buy both together or accept a very annoying wait. Our record for it carries the title Lirael Daughter of the Clayr, published as Lirael: Daughter of the Clayr.
Then Across the wall, a short story collection whose reason for existing here is the opening novella about Nicholas Sayre, which is set after Abhorsen and sets up what follows. The rest of the collection is unconnected fantasy and science fiction, some of it very good, none of it required.
Goldenhand continues the main line after the Nicholas Sayre novella. The two prequels, Clariel and Terciel and Elinor, belong after that: the first is the deep history of the Abhorsen line, the second is about Sabriel's parents and reads as a quiet companion piece rather than an adventure.
Publication order also happens to be the order Nix wrote them to be read. The chronological order is Clariel, Terciel and Elinor, Sabriel, Lirael, Abhorsen, Goldenhand, and it works only as a re-read.
The Keys to the Kingdom
A separate seven-book sequence for younger readers, one book per day of the week, and strictly sequential — this one really is a single story chopped into seven. Our list holds the first four: Mister Monday, Grim Tuesday, Drowned Wednesday and Sir Thursday. The remaining three, Lady Friday, Superior Saturday and Lord Sunday, are not in our catalogue, and starting the sequence without a plan for finishing it is unsatisfying because the ending resolves everything at once.
It is pitched younger than the Old Kingdom and moves faster. Read it alongside the Old Kingdom rather than in place of it.
The standalones
Shade's children is Nix at his darkest: a science fiction dystopia in which adults have vanished and children are farmed for parts. It is short, grim and has nothing to do with the Old Kingdom.
Angel Mage is a secondary-world fantasy with a strongly seventeenth-century French flavour and an unusual magic system built on summoned angels; readers are divided on its pacing. The Left-Handed Booksellers of London is the lightest thing here — an urban fantasy set in 1983 London, with booksellers who police the old magic, and it has a sequel not in our list.
Several other Nix sequences exist and are absent from this catalogue, including The Seventh Tower, A Confusion of Princes, Frogkisser! and The Ragwitch. Their absence is ours, not a judgement.
Where to stop
After Abhorsen, honestly, if the Old Kingdom is all you want — the first three books form a complete arc. Everything after is genuine continuation rather than padding, but that is the natural stopping point, and the rest of the catalogue is a reasonable next move if you would rather try something else.
Follow the full ordered path here: Garth Nix books in order: where to start with the Old Kingdom.
