The Forger's Shadow, by Nick Groom

Early in The Forger's Shadow Nick Groom lists the handful of facts readers may know about Thomas Chatterton: he was a Romantic poet; he died young, like Keats; he committed suicide; he forged medieval poetry; he came from Bristol; a Pre-Raphaelite painting of his death hangs in Tate Britain; and Peter Ackroyd wrote a novel about him.

Groom is our leading Chatterton enthusiast. One aim of his book is to untangle the real life from the posthumous image of the poet Wordsworth called "the marvellous Boy" and who served Coleridge and Keats as the archetype of youthful English genius. An intriguing forensic investigation suggests that Chatterton did not commit suicide but accidentally poisoned himself with arsenic (taken as a cure for the clap) and opium (painkiller).

Groom's second aim is to place Chatterton in the company of some colourful near-contemporaries: James Macpherson, the Scotsman who claimed to have discovered the works of "Ossian", the lost father of Gaelic poetry; William Henry Ireland, the teenager who in 1796 conned literary London into believing that he had unearthed a chestful of original Shakespeareana; and TG Wainewright, the Romantic essayist, forger and purported poisoner, about whom Andrew Motion wrote a biography-cum-novel.

Groom offers an apologia for this motley crew. With Chatterton he is on strong ground: poems he wrote in the voice of a medieval bard called Rowley brim over with accomplishment. Macpherson, too, has been rehabilitated. Far from being outright forgeries, the Ossianic fragments included material gathered from authentic songs and tales.

With Ireland, Groom is on rockier ground. Ireland was a naïve faker who got into the lucrative business of penning Shakespeare manuscripts to please his dad, a publisher. Blake's visionary universe would not have been possible without Ossian; the sensuousness of Keats owed a debt to Rowley; but Ireland's manufacture of Shakespeare's Kynge Vorrtygerne was more a farce in the manner of the Hitler diaries.

His ambition of is to suggest that Chatterton, Macpherson and co were the true progenitors of Romanticism. You thought that Romanticism was all inspiration, originality and authenticity? Wrong. It took its bearings from imitation, forgery and impersonation. Like all such revisionary readings, this one builds kernels of truth into castles in the air.

Groom takes risks in combining jeux d'esprit with scholarship, notably in the case of Binjamin Wilkomirski's Fragments (1996), a faked concentration camp memoir. Should it be regarded as a powerful novel or immoral imposture? The conclusion rolls a little too glibly off the tongue: "I thought we already knew that writers can often spin a bewitching yarn."

This is a book of prodigious and quirky learning. At the same time, rudimentary errors are scattered through the text, as when AC Swinburne mysteriously becomes "CA". It is not clear whether the lapses are the result of carelessness or a plot – hatched in accordance with the theme – to subvert the values of "authentic" scholarship.