Caesar: The Life of a Colossus, by Adrian Goldsworthy

It was only too easy to underestimate Julius Caesar. Talented, amusing and fashionable, he had a voracious appetite for cash and built up enormous debts. He spent much of his leisure time chasing the wives of his political colleagues; it was rumoured that he slept with men as well. He was very attentive to his appearance, always keeping his head carefully trimmed and shaved, and depilating his pubic hair. Caesar's contemporary, the great orator Cicero, remarked that: "When I notice how carefully arranged his hair is and when I watch him adjusting the parting with one finger, I cannot imagine that this man could conceive of such a wicked thing as to destroy the Roman constitution."

In fact, the charm and the foppishness veiled determination and high intelligence, which his opponents did not immediately recognise. Caesar was born in 100BC and entered politics at a time when the constitution of the Roman Republic was coming under severe strain. An oligarchy with elements of democracy, Rome was governed by a cacophony of competing noblemen. It was no way to run one of the largest empires the world had yet seen.

Caesar, coming from a "left-wing" but aristocratic family background, always fought for popular rights and did everything he could to subvert the ruling class. As a general he was famous for his celeritas, his speediness. He insisted on holding the initiative, at whatever cost; if there was trouble he rushed to the heart of the action.

As in the field, so at Rome. Caesar was a practical politician who responded to events in the Senate or Forum by a cascade of brilliant and daring improvisations. In 59BC he entered into an alliance with two other powerful populares, Crassus and Pompey the Great, and for a number of years the three men were, in effect, masters of the state, to the fury of the Senate. After holding the Republic's top job, the Consulship, Caesar became a provincial governor and spent 10 years invading and annexing Gaul (modern France). When his term came to an end, his enemies at Rome were set on revenge. They planned to prosecute him for breaking the law and so terminate his career. Faced with their recalcitrance, Caesar precipitated a civil war, which he won after a series of quick-fire campaigns.

Now undisputed ruler of Rome, he knew he could not govern alone, and did his best to conciliate his fellow noblemen. They could not forgive his pre-eminence and formed a conspiracy to assassinate him, a task accomplished on 15 March 44BC.

Adrian Goldsworthy is the latest in a long line of scholars to write the life of this remarkable man, who brought down the Republic and prepared the way for the first of the emperors, his adopted son Augustus. He is a sober, comprehensive and fair-minded writer, who gives every topic its due attention. The scholarship is up-to-date; the judgements sound. I have only a few quibbles: for example, Caesarion was not the name that Cleopatra gave to her son by Caesar, but a nickname conferred by the Alexandrian populace.

So it is a pity that Caesar: the Life of a Colossus sometimes reads more like a textbook than the biography of a flesh-and-blood being. Paragraphs are of Proustian length. Future events are frequently discussed in advance, dampening narrative suspense.

But Goldsworthy is a fine military historian and his account of the Gallic Wars is exemplary. He always remembers the common soldier and evokes with great skill the terrifying experience of hand-to-hand fighting.

One central mystery is unsolved and must remain so. Was Caesar an adventurer with luck, a typical Roman aristocrat only concerned with his glory - or a visionary with a new plan for the governance of Rome? It may well be that Julius Caesar was the thinking man's opportunist - a dynast who pursued his own selfish interests, but had ready a blueprint for radical change just in case it were to come in handy.

Anthony Everitt's life of Augustus will be published by John Murray in October