Machiavelli, By Ross King

The Florentine idealist had many cunning plans, but most of them didn't work

Authorities on statecraft and strategy often come a cropper when they have the chance to put their cherished theories into practice. Niccolo Machiavelli had already failed more than once to make his beloved Florence as secure as his principles demanded when, in 1526, he was invited on to a parade ground in Lombardy to drill the troops of the Holy League. The mercenary captain Giovanni de'Medici had read Machiavelli's Art of War but doubted that this intellectual diplomat and politician really knew how to run an army. Sure enough, chaos reigned. Giovanni had to resume command, declaring that "Niccolo knew how to write things well and he knew how to do them".

Machiavelli's later reputation as Europe's first open advocate of ruthless and deceitful realpolitik has paradoxical foundations. First, the Florentine fixer-turned-thinker tended to make a hash of things when circumstances called for merciless determination on the ground rather than in the mind. Second, the shameless lessons in what we now call not just "spin" but "shock and awe" in The Prince account for one brief part of a 30-year career marked more by thwarted idealism than rat-like cunning.

Weakened by its dithering merchant elite and the erratic quasi-monarchs of the Medici clan, the Florence of his lifetime (1469-1527) never did live up to Machiavelli's dream of a frugal and sturdy republic. Yet he spent, or wasted, his best years trying to serve it.

As much for the Discourses on Roman republican virtues as for the dark arts of force and guile in The Prince, Machiavelli stands at the centre of modern political thought. As Ross King writes, he has been "conscripted into service by adherents of varying political outlooks".

Wisely, this engrossing short biography refuses to add to the pile of interpretations. Instead, King marries his lightly worn expertise in the Italy of 500 years ago with a flair for rooting cultural landmarks in earthy realities. His Machiavelli spends almost as much time in taverns and brothels as on the battlefield or in the council chamber.

Above all, King knows how to plant the flowers of the Renaissance amid the squalor and danger of their time. In 1515, the Medici pope Leo X returned to Florence for a lavish festival to celebrate the family's "Golden Age". This was symbolised by covering a young boy in gold paint. It "destroyed his skin and killed him three days later". Welcome to Machiavelli's glittering, toxic world.

Harper Press, £14.99. Order for £13.49 (free p&p) on 0870 079 8897