These Old Shades is probably the best-loved of all Georgette Heyer's Regency romances.

Our hero, if he can be so described, is Justin Alistair, Duke of Avon, and archetypal "bad boy". In his forties, Avon is a rake, a gambler, and a cynic. He's urbane, intelligent and charming where he chooses to be, but also sarcastic, vindictive and a tyrant to his servants. He holds grudges too, often for a preternatuarally long time, and it's one of these grudges that drives the entire action of the novel.

Avon is walking on the streets of Paris one night when he is run into by a youth, Leon, who is fleeing punishment, pursued by his brother. Recognising the distinctive colouring and features of an old enemy in the boy's face, Avon whimsically purchases him from his brutish sibling body and soul for the cost of a jewel. He takes the boy home and makes him his page, earning his complete devotion.

This being a romance, and written in 1926, it will come as no surprise that Leon turns out to be Leonie, a girl of nineteen, beautiful, vivacious and full of paradoxical gamin innocence and world-weary experience, who the Duke adopts as his ward. Leonie is, frankly, a complete darling, and there's barely a character in the novel who doesn't come to love her - and barely a reader, either. At the time the story opens, she's been masquerading as a boy for seven years, and adapts slowly and incompletely to the behaviour expected of a "young lady", retaining a freshness that makes her an instant hit in society when she makes her debut.

The supporting cast of characters includes a villainous French Count, his mousy wife, clodhopping son, and envious younger brother; Avon's oldest friend, a sober gentleman who often vocally despairs of the duke's wild behaviour; Lord Merivale and his wife, Jennifer, country gentlefolk who haven't spoken to Avon since he attempted to abduct my lady prior to the wedding; a gaggle of servants, French and English, who universally loathe and fear their master; a saintly priest; a prince of the blood and the dysfunctional family of which Avon is the patriarch. This family consists of sister Fanny a spoiled, shrewd and often silly woman of fashion, her stodgy husband, and Rupert, the youngest sibling, a well-meaning scamp with a leaning towards heroism. Last, but not least comes Mr Manvers, a bumptious squire, and the owner of a significant roan horse.

The action moves from France to England and back again. Much of it deals with Leonie's reluctant re-education in femininity, but there's plenty of action too. There are fencing lessons as well as dancing lessons, brawls as well as balls, a kidnapping and pursuit, gunshot wounds, betrayal, despair and a couple of suicides, a revenge scene played out by Avon, with tremendous style and the inevitable, romantic happy ending. It's a delightful romp.

What lifts a Heyer novel above a run-of-the-mill historical romance, however, is sheer quality of writing. She has a fanatical attention to detail, which makes both dialogue and setting absolutely authentic, but she couples it with a wit and lightness of touch that makes even her lovingly precise descriptions of clothing a pleasure to read. This quality is never more evident than in this book and its sequels Devil's Cub and An Infamous Army (which is so good a picture of the events leading up to and during the battle of Waterloo that it's often a set text at Sandhurst Military Academy). Conversations sparkle, characters, even minor ones, leap off the page, and readers get completely caught up and swept along through ballrooms, inns, countryside and events at a cracking pace.

It's too good a read to be considered literature, but it's written with consummate skill.