|Cover artist||Sandra Nobes/Hofstede Design (paperback, Allen & Unwin)|
|Series||The Keys to the Kingdom|
|1 March 2006|
|Media type||Print (paperback & hardcover)|
|LC Class||PZ7.N647 Sir 2006|
|Preceded by||Drowned Wednesday|
|Followed by||Lady Friday|
Sir Thursday is a young adult fantasy novel written by Australian author Garth Nix. It is the fourth book in The Keys to the Kingdom series, and was released in March 2006. Sir Thursday continues from the preceding book, following the adventures of Arthur Penhaligon as he attempts to retrieve the Fourth key of the Kingdom, and claim mastership of The Great Maze. As with the other books in the series, the theme of 'seven' is prevalent, along with the themes of sin and virtue. The book received generally favourable critical response, but was criticised for a slow pace, among other issues.
The book begins with Arthur Penhaligon and Leaf attempting to return to Earth after their adventures in the Border Sea. While Leaf is able to pass through the front door and return to Earth, the presence of a Nithling duplicate of Arthur prevents him from doing so, and he is forced to remain in the Lower House.
Dame Primus then informs him that Mister Monday and Grim Tuesday have been assassinated. Moments later, he is drafted into the Glorious Army of the Architect – wherein everyone living in the House must serve for 100 years – which is based in the chessboard-like demesne called the Great Maze. The leader of the army is the Fourth Trustee of the Will, Sir Thursday, a Denizen afflicted with the deadly sin of wrath. The army is currently involved in a campaign against the Piper, who is trying to claim the Fourth Key.
Within the army, Arthur is soon mistaken for a Piper's child and has his memory wiped, along with his friend Fred Initials Numbers Gold – a real Piper's child. One month later and during the first battle against the Piper's New Nithling army, Arthur begins to recall his identity. The entirety of it is recovered later in the book when an officer mentions his name and title.
On Earth, Arthur's double, known as the Skinless Boy, has thrown a hospital near Arthur's home into panic by infecting staff and patients with a fungoid, extraterrestrial life-form which allows him to read and eventually control their thoughts and actions. This fungus, nicknamed Grayspot, is mistaken for a biological weapon, and the hospital put under quarantine. Leaf infiltrates the hospital, seeking to obtain and destroy the magical object used to create the Skinless Boy: a pocket torn from one of Arthur's shirts. She succeeds, but is infected by Grayspot in the process. She then leaves the hospital, only to find that the House has appeared above it and cannot be reached from the ground. With the help of a retired pharmacist named Sylvie, Leaf makes her way to Arthur's house where she uses a special telephone to contact Arthur's friends and get help, just as the fungus gains full control of her body.
Suzy Turquoise Blue arrives and takes the pocket to the House. There, she finds Arthur and Fred, and joins them in a raid led by Sir Thursday to find and destroy the New Nithlings' weapon, which is preventing the mechanical floor of the Great Maze from shifting. Arthur destroys the weapon by throwing the pocket into it, simultaneously destroying the Skinless Boy. As Arthur escapes from the Piper with Sir Thursday, he distracts Thursday enough for the fourth part of the Will, a snake embodying the virtue of justice, to break free, whereupon it makes Arthur the Bearer of the Fourth Key – a sword or baton depending on whether or not the wielder is in combat – and Commander of the Glorious Army of the Architect. With help from Dame Primus and others from the lower demesnes, Arthur defeats the New Nithling army.
On Earth, Leaf wakes up in a hospital a week after the Skinless Boy was defeated. She soon learns from a nurse that the Grayspot has disappeared and that Lady Friday, another Trustee, has become a doctor on Earth.
- Arthur Penhaligon – The protagonist of the book, Arthur is a human asthmatic, who was chosen by the Will of the Architect to become the Rightful Heir to the house. He owns the First, Second, and Third Keys, but is not in possession of them throughout most of the book. Arthur shows a strong sense of right and wrong, as well as a reliance on friends and allies to achieve his goal: the rightful mastery of the entire House.
- Dame Primus – The embodiment of the Will, who consists in Sir Thursday of the First, Second, and Third parts of the Will. She is portrayed as caring little for others, becoming easily annoyed if they seem to be slowing the process of restoring the House.
- Sir Thursday – Sir Thursday is the fourth Trustee of the Will, and is afflicted with the sin of Wrath. He is a military Denizen, and believes in order and control. The Will breaks free from him when Arthur makes him sufficiently angry.
- Leaf – Leaf is one of Arthur's few human friends. She supports him in Sir Thursday by retrieving the pocket that supports the existence of the Skinless Boy.
- Suzy Turquoise Blue – Suzy Turquoise Blue is a Piper's Child, and another friend of Arthur. She also aids him in his adventures, and joins Arthur in the army in order to pass him the pocket.
- Part Four of the Will – The Fourth Part of the Will, embodying the virtue of justice, takes the form of a snake. It is released by Arthur near the end of the book when he makes Sir Thursday angry.
- Fred Initials Numbers Gold – A Piper's Child drafted into the army the day before Arthur, Fred provides him with information and support until the end of the book, where he is missing, having been captured by the Piper.
- The Piper – The Piper, one of the children of the Architect and the Old One, claims to be the Rightful Heir, and lays siege to the Citadel in the Great Maze to wrest the key from Sir Thursday.
As with the previous books in the series, the themes of seven, sin and virtue are prevalent throughout Sir Thursday providing the personality characteristics for many of the main characters.
In Sir Thursday, readers are also introduced to the power issues that Arthur begins to struggle with – his natural compassion and desire for fairness and kindness, against the characteristics displayed by other senior denizens and Dame Primus, and the influence of the key. In addition, the idea of Arthur losing his mortality and becoming an immortal Denizen of the House, represented by the silver/gold crocodile ring that was introduced in Drowned Wednesday, is further explored, with Arthur often choosing to refrain from using the key – and the power it represents – to ensure he remains human.
The book also loosely explores the dangers of anger, and actions taken in anger. It is only Sir Thursday's loss of control and subsequent murder of two Piper's Children that allows Arthur to gain control of the Fourth Key, assisted by Thursday's Dawn, Noon and Dusk.
In particular, the book was praised for its originality, intricacy, action and characters. VOYA says that the book "..is well written, action packed, imaginative, and full of quirky memorable characters...", and Children's Literature agrees that "It is a readable choice..." The School Library Journal also extensively praised the book, saying "Reluctant or 'hard to fit' readers will find this series enjoyable, as Nix is able to create vivid pictures in the minds of his readers. Fans of the fantasy genre will appreciate these books for their strong continuity, believable characters, and edge-of-your-seat-action. This offering complements the series’ well-established structure."
The book did, however, receive consistent criticism. The most common complaint was on the speed of the plot – the School Library Journal summarises all the comments, saying that "the events move a little slower than in previous installments..." – and the difficulty in entering the series without reading all the previous books first: VOYA simply says "readers attempting to enter the series through this volume are likely to be quickly lost." Children's Literature also criticised the repetition of previous content, saying there is "..entirely too much front matter [which] sags with the necessity of replaying earlier story lines."
- "Amazon.com Book Details". 1 March 2006. Retrieved 2008-09-27.
- R. J. Carter (25 March 2006). "The Trades". Retrieved 2008-09-27.
- Nix, Garth (2006). Sir Thursday. Great Britain: HarperCollins. p. 408. ISBN 0-00-717507-8.
- Nix, Garth (2006). Sir Thursday. Great Britain: HarperCollins. p. 57. ISBN 0-00-717507-8.
- Nix, Garth (2006). Sir Thursday. Great Britain: HarperCollins. p. 394. ISBN 0-00-717507-8.
- Nix, Garth (2006). Sir Thursday. Great Britain: HarperCollins. pp. 55, 56. ISBN 0-00-717507-8.
- Nix, Garth (2006). Sir Thursday. Great Britain: HarperCollins. pp. 373–376. ISBN 0-00-717507-8.
- Nix, Garth (2006). Sir Thursday. Great Britain: HarperCollins. pp. 370–377. ISBN 0-00-717507-8.
- "Amazon.co.uk Reviews". Retrieved 2009-05-17.
- "Amazon Product Description". Retrieved 2009-05-17.
- Levy, Michael (2006). "Sir Thursday by Garth Nix". VOYA. 30 (1).
- "Children's Literature". Retrieved 2009-10-30.
- "School Library Journal". Retrieved 2009-05-17.