The Janissary Tree by Jason Goodwin

But in his non-fiction Goodwin, an an engaging enthusiast, never bludgeons the reader with his learning; he shares it excitedly. And now he does so in fiction.

The Janissary Tree puts us in Istanbul, 1836. Steaming tanneries stink of the dog faeces used to tan hides; cramped markets are fat with an Empire's produce; dervishes whirl for coins; the Imperial Archive bulges with 400 years of bureaucratic reports.

The hero has access to every cranny and alley of Istanbul life. He is Yashim, a retired Court eunuch, reserved and dapper in his cashmere cloak, an investigator for the Empire's elite; in effect, a detective. Past adventures in the Crimea are hinted at and now there's trouble at the palace.

A young officer of the westernised New Guard is found stuffed in a cooking pot in the Royal stables, his face sliced off. Three more officers are missing. In a side-plot, a young harem godze (a glossary would have been handy) is strangled on her way to the bed of Sultan Mahmut II, and jewels presented by Napoleon to the Sultan's mother, the Validé Sultan, are stolen.

Things being slower in 1836, our detective has 10 days, not 48 hours, to find the guilty. The proclamation of a liberal Edict from the Sultan and a grand public review of the New Guard are due, and the Court doesn't want unsolved murders raining on its parade.

For Yashim, the clues suggest the Janissaries. Once the Sultan's elite troops, they grew violently corrupt and more interested in making than protecting Sultans. Ten years before the action they were massacred by the New Guard, but thousands escaped. Their bizarre rallying drumbeat had been wooden spoons on cooking pots and after the potted officer's death, new corpses turn up with wooden spoons attached at the base of old Janissary watchtowers.

As Yashim searches high (the harem, embassies, mosques) and low (dodgy bars, back alleys, the tanneries) he is helped by Preen, a shrewd, sad köçek (transvestite dancer) and the Polish Ambassador Palieski, the vodka-downing representative of a land long since swallowed by its neighbours.

The hero stifles the lust he still feels with a passion for literature, cooking and the world of the mind. It gives him a dignity, melancholy and separateness perfect in a detective. Goodwin has created a subtle character that deserves to endure.

So when Yashim is bedded by a raunchy Russian beauty, it breaks an elegantly created spell. (There were grades of castration apparently, and while we get no details, Yashim's privates can at least stand to attention.)

The only other false note is the anachronistic speech of Istanbul's toiling masses. Every "Whatever" or "lovely job" transports us to the Queen Vic. And from page one, we don't want to be there; we want to be in Istanbul with Yashim, as time runs out, the plot strands twine together and hidden Janissaries sharpen their blades.