God's Jury: The Inquisition and the Making of the Modern World, By Cullen Murphy

Television has been widely credited with making history fashionable again, with all those enthusiastic and engaging experts taking to the small screen. They have hauled what had become too often a subject constrained by the lifeless prose of academic books into the mainstream of public debate. Now there seems to be traffic the other way, for there is something televisual about God's Jury, an enormously enjoyable and very modern history of the Inquisition by Cullen Murphy, editor-at-large of Vanity Fair.

He is not content with just slipping in the standard reference, in the small industry of books on the topic, to Monty Python's "No one expects the Spanish Inquistion" quip. Instead, he sets out to walk and talk his way through his subject, right up to the present day. The absence of moving images is scarcely an impediment. Murphy has a way with words and, with the choice of beguiling stopping-off points, this reader forever had a vivid picture running in my mind.

God's Jury is part travelogue, part polemic, with a tiny smattering of memoir. Murphy is a Catholic, albeit, to judge by his choice of modern theologians, of the liberal variety. He starts inside the Vatican's archives, only recently opened to the public, then makes his way through the various manifestations of the Inquisition. For it was never a single entity. Like the Catholic church that it served, it may have claimed continuity and universality but took on different forms depending on the soil in which it sprang up.

The first coming was in southern France in the 13th century, where a papacy that had expanded to claim authority across western Europe was facing a little local difficulty in the shape of the Cathars: clean-living, pious Christian folk who regarded this world as the creation of the Devil and the Church as doing Satan's business. The Inquisition was established to bring them back in line by torture, public executions and the cultivation of such paranoia that husbands turned in their wives, neighbour spied on neighbour, and woe betide anyone who stood out from the norm.

Sounds familiar? Murphy introduces at this early stage his key thesis – namely, that the Inquisition was thoroughly modern in its techniques. Persecution had been around for as long as there were two human beings to pick on each other, but this apparatus of total Catholicism perfected methods that remain with us: a bureaucracy of oppression, control of information, the cloak of legal justification rooted in institutional power, and, above all, a ruthlessness that came from the sincere belief that it was 100 per cent right. Compare and contrast this "inquisitorial impulse", Murphy challenges, to those that have arisen since – the gulags, the generals in Argentina's "Dirty War" and Guantánamo Bay are but three he quotes.

He builds his case patiently and convincingly, with plenty of references to George Orwell, as he continues his travels to the scene of the second coming of the Inquisition – the reunited Spain of Ferdinand and Isabella in the latter 15th century. It set up shop there to target all who did not fit into the Catholic identity the new kingdom had chosen to adopt – Jews, Muslims, and recent converts to the faith. And it threw up in Tomas de Torquemada the most notorious inquisitorial mastermind of all. Like many persecutors, he seems to have been driven, by some deep-rooted, self-loathing impulse, to target in others what he disliked in himself: namely, Jewish blood.

The Spanish Inquisition dragged on until the 19th century, when it took the invading armies of Napoleon to dislodge it. But it lived on even longer in Rome itself, since the Pope remained until 1870 a temporal as well as a spiritual prince. Even after the united Italy made the pontiff a "prisoner in the Vatican", the Inquisitorial mindset continued to pollute the lives of Catholics, with its Index of prohibited books that Murphy links to current campaigns to restrict freedom of expression on the internet. The major Vatican department today, the Congregation for the Doctrine of the Faith, once headed by the current Pope, is in name and deed the heir to the Inquisition, Murphy concludes.

Even the jacket of this book is modern – a juror's chair rather than a medieval image of some poor individual being torn limb from limb on the rack in an effort to convince them to break their alleged pact with the Devil. The twin narratives – ancient and modern – might make for a clumsy device, but Murphy's touch, tone and emphasis are never anything but sure and sane. This is popular history at its very best.

Peter Stanford's history of cemeteries will be published this year by Bloomsbury