Treason's Harbour is the ninth historical novel in the Aubrey-Maturin series by British author Patrick O'Brian, first published in 1983.

While with Captain Jack Aubrey awaiting repairs on his ship in Malta, Stephen Maturin discovers that the island is home to a ruthless network of French spies.

"[1] Another gives negative reviews to a particular narrator of an audio version by praising O'Brian's writing: "characters' voices lack consistency and sensitivity to the subtleties of O'Brian's pen";[2] and yet more strongly, "The narrative turns from nefarious intrigues in Malta to an amazing mission in the Red Sea and back again, but the drama is [not] conveyed .

The new Commander of the Mediterranean fleet, Admiral Sir Francis Ives and acting second secretary Andrew Wray, arrive in Malta with their own advisor on Turkish affairs.

Aubrey is dispatched on a secret mission by Admiral Ives to capture a Turkish galley laden with French silver in the Red Sea.

They sail on the Dromedary to Tina, and then walk across the Sinai Peninsula to meet the HEI ship Niobe at Suez.

Maturin and Aubrey use the diving bell to retrieve the cargo, but find it is lead not silver, a complete trap.

They reverse the challenging journey, offloading the disappointed Turkish troops at Suez, then cross the desert with no escort.

Only Aubrey’s chest, with his chelengk award and the dead dragoman’s papers, is saved by Killick’s diligent effort.

Before dispatching Surprise to England, Ives asks Aubrey to take the Adriatic convoy up to Trieste, where he meets Captain Cotton of HMS Nymphe.

While Pollux waits at the entrance of the Bay of Zambra, the French Mars with two frigates fire on her, with a fierce ensuing battle.

[2] Of the reader of this audio book, they said "Royal Shakespeare Company and National Theatre actor Pigott-Smith has an appropriately English accent, but his characters' voices lack consistency and sensitivity to the subtleties of O'Brian's pen.

[2] Further, readers of this series "will despair at hearing how this production tramples upon his genius in portraying shockingly real characters in an utterly foreign, far-off time.

"[2] Patrick Reardon, writing in the Chicago Tribune when the paperback was issued in the US, mentions the incident of Mr Hairabedian's abrupt demise.

In assessing that shocking scene and the crew's reaction to it, Reardon says that "Not much happens in O`Brian`s books, not much, that is, in the sense of battles and great drama.

"[1] Most of the novels in the series tell the story exclusively from the point of view of Maturin or Aubrey, either through descriptions through their eyes, direct conversations, their internal thoughts, or their letters and diary entries.

[4] Thus from the opening pages of the novel, the reader is aware that Wray, the acting second secretary of the British Admiralty, is secretly accepting money and taking orders from France.

In fact, one of his last actions in the book is to write a letter to Wray detailing his suspicions and describing the French spy network in Malta.

Beginning with The Nutmeg of Consolation in 1991, the novels were released at about the same time in the USA (by W W Norton) and the UK (by HarperCollins, the name of Collins after a merger).