Newton and the Counterfeiter, By Thomas Levenson

The gripping story of how Britain's premier scientist saved the Treasury from a quite remarkable rogue

The present downturn is as nothing compared with the economic crisis England faced in the 1690s, after widespread counterfeiting and clipping (the trimming of valuable metal from the edges of coins) debased the currency to the extent that the Chancellor reported that only one in every 2,000 coins contained the correct amounts of silver. William III, who couldn't afford to pay the army he was employing to wage war against Louis XIV and France, begged Parliament to do something about "the ill State of the Coin", so William Lowndes, the secretary to the treasury, wrote to each of the nation's most prominent thinkers for help. Which is how, a decade or so after his Principia Mathematica had propelled him to the vanguard of the ongoing scientific revolution, Isaac Newton came to be appointed warden of the Royal Mint.

Also apparently vexed by the state of the nation's coinage was the author of the 1694 pamphlet "Proposals Humbly Offered, for Passing, an Act to Prevent Clipping and Counterfeiting of Money": a certain Mr William Chaloner, the other subject of Thomas Levenson's enormously entertaining dual biography. The illiterate son of a weaver, born in Warwickshire a decade or two after Newton (Levenson is rescuing him from obscurity and some biographical details are lost), Chaloner arrived in London in the 1680s with only a few years' experience as a blacksmith's apprentice and "an elastic moral sense". According to Chaloner's only other biographer – the anonymous author of a sensationalist true-crime book written immediately after his execution – "The first part of his Ingenuity showed it self in making Tin Watches, with D-does &c in 'em." That is, Chaloner first made his mark in the capital as a purveyor of sex toys. Next, "having the best knack at Tongue-pudding", he established himself as a quack doctor and soothsayer, "pretending to tell sill' Wenches what sort of Husbands they should have, discovering Stol'*Goods &c".

The trick Chaloner devised to recover stolen property was the obvious one: he stole it in the first place. As a result, he makes his first appearance in the public record in 1690, as a suspect in a burglary case. But the tongue-pudding and the knack for playing two sides against each other would remain the hallmarks of his increasingly large-scale criminal enterprises.

By the time of Newton's appointment to the Mint, Chaloner had become one of the country's most prolific counterfeiters, bought a large house in the semi-rural suburb of Knightsbridge with the proceeds, and, as Newton later noted, "[had] put on ye habit of a Gentleman". It was in the guise of a knowledgeable but respectable citizen offering his services (but with the ultimate aim of gaining access to the Mint and its tools for himself) that Chaloner began to petition parliament. But he went too far. In publicly accusing the warden of the Mint of incompetence, he made a formidable enemy. Newton, easily slighted and liable to hold a grudge, was to be Chaloner's nemesis.

The subtitle of Newton and the Counterfeiter promises us "The first scientific detective story". Levenson, who is professor of science writing at MIT, gives a good account of Newton's life and work, and how he did as much as any to establish the scientific method and the rationalist notion that material events have discernible material causes – without which no detective can follow a trail of clues leading to his or her culprit. But this isn't really that kind of detective story. Instead, Newton used time-honoured policing methods: recruiting a network of informers, interrogating and intimidating witnesses, and "all in all, diving as deep as needed into the muck of the capital's criminal landscape".

Ironically, Levenson's book becomes a less compulsive page-turner in its final section, in which he gets bogged down in the detail of the case Newton built against Chaloner. But that is a small price to pay for the diligence with which he has unearthed his story; painted a colourful portrait of two fascinating characters against the backdrops of England's scientific and criminal communities; and sketched the political, economic and cultural landscape of England at the dawn of the modern era.