IN THE VAST SWEEP of the Napoleonic wars, the Peninsular, as the English with characteristic understatement call the Iberian theater, formed a relatively minor sideshow. A bleak and backward country at the beginning of the 19th century which seemed to merit in full measure the popular observation that "Africa begins at the Pyrenees," Spain was the one place where Napoleon's magic, albeit in the hands of his apprentices, failed to work. "Disperse to feed, unite to fight" had produced Austerlitz, Jena, and a Pax Gallia in Europe. In Spain, it produced only disaster.

The problem for the French was the 30,000 or so guerilleros who roamed the countryside terrorizing and bullying the peasants into resistance, bushwhacking and murdering (usually with extreme cruelty) isolated groups of Frenchmen. Alone, the guerilleros would have offered no more than a considerable nuisance to the French invaders. However, in combination with the British army under Wellington, they produced an insoluble strategic dilemma for Napoleon's marshals: "If I concentrate 20,000 men," wrote General Bessieres, worn out by the chasse aux partisans, in 1811, "all my communications are lost and the insurgents make great progress. We occupy too much territory." That was fine by the Iron Duke -- if the French concentrated overwhelming numbers against him, they forfeited hard-won "pacified" areas to his allies, while the English would drop back toward Lisbon refusing battle. If the French held on to their territory, they could never bring the full weight of their superior numbers against the tough but small British force. This produced an odd sort of war which seemed to belong half to the 18th century, half to the 20th, and explains why men of a Napoleonic stamp could never quite figure it out.

Wellington was a patient man. He pursued the French unhurriedly, aggravating Napoleon's "Spanish ulcer" until, after six years of campaigning, it finally hemorrhaged across the Pyrenees into France. These were six hard years, made even harder by Wellington's exacting standards which sometimes proved too harsh for his staff: "J'ai horreur de deux mots," complained Wellington's Spanish liaison officer, forced to conform to his English commander's matinal habits, "daylight et cold beef."

It is hardly surprising that great events such as the Peninsular Wars attract writers of historical fiction -- the setting and the broad outlines of a plot are provided. The task of the writer is to supply a hero. The one provided by Barnard Cornwell is a corker -- Richard Sharpe. In an era when officer rank was purchased by gentlemen, Sharpe is quite the exception. A ranker who, after saving Wellesley's life in India, gains a commission through courage rather than cash, Sharpe remains one of nature's NCOs struggling to come to terms with his exalted status. Not that he has been promoted above his abilities. Quite the contrary, Sharpe earns the respect of the men which is withheld from the brave but dandified officers whose companies and regiments are acquired by auction at the Horse Guards. He is condemned to suffer the most unjust of indignities in British eyes -- to be bypassed by queue jumpers with money. In fact, it is clear that Sharpe is fighting for the wrong side. In the French army of Napoleon, careers were open to talent. There he could be, if not a marshal of France, at least the commander of a division.

Sharpe makes his way in the British army because he is brave and because he is indestructible. Wellington's favor also has something to do with it, for the general is in the business of giving second chances to a man whose impetuosity, lack of deference and sheer common sense constantly land him in hot water.

IN Sharpe's Honour, the sixth of Cornwell's Sharpe novels, the Peninsular Wars are drawing to a close. The French are retreating toward the Pyrenees. Alliance politics being what they are, however, some unscrupulous Spaniards led by a priest of the Inquisition stike a last-minute bargain with a calculating French intelligence officer to release their captive king, Ferdinard VII, against a promise to allow the French to withdraw unmolested. (The notion is improbable, but never mind.) Of course, Sharpe becomes a strategic piece in this Jesuitical jigsaw. The bait is an astonishingly beautiful Frenchwoman who seems to be employed mainly in sleeping her way through the Spanish aristocracy and the French high command, with occasional excursions into the beds of the BEF. She proves quite willing to barter her affection for Sharpe in return for a promise of safe passage for her ill-got wealth out of Spain in the baggage trains of the French army. All she need do is write a letter which will provoke a duel between Sharpe and her husband, a chinless but influential Spanish nobleman whose death at Sharpe's hand would help drive a wedge into the Anglo-Spanish alliance.

In many respects, this is one of the least successful of Cornwell's novels. The plot does not so much thicken as congeal. Sharpe never seems fully to grasp the conspiracy into which he is drawn, pursuing a fallen woman (whose interest in our hero is no more elevated than his belt line) through partisan dens, a nunnery, and French fortresses like a hyperactive Errol Flynn. Cornwell is at his best describing sieges and battles. While his fine eye for detail remains his forte, his usually concentrated narrative and extraordinary knowledge of the period (down to the company which manufactured French cavalry sabres) is rather dissipated in this fissiparous picaresque, from which the bold and amorous Sharpe emerges looking more like Don Quixote than Don Juan.

Cornwell does not write historical fiction in the grand tradition of Thomas Keneally's Confederates or Thomas Flanagan's The Year of the French. But he certainly knows how to scribble a ripping yarn. Sharpeophiles will devour this tale, which takes the Major one step nearer Waterloo. Those who wish to see how James Bond looks in kneebritches should begin at the beginning.