The Quarrel of the Age: the Life and Times of William Hazlitt
AC Grayling
Weidenfeld and Nicholson £25, pp399
Buy it at BOL

'I wish people made larger paper,' wrote William Hazlitt at 12. Even in childhood there seemed too many thoughts for his page, before he became one of the most astonishing writers of the Romantic age. Bare-knuckled controversialist, plangent lonely heart, impassioned theatre and art critic, he reinvented journalism and the essay. His favourite quality in art was 'gusto', which animates his own prose.

AC Grayling (philosopher and broadsheet regular) is drawn to the critic-metaphysician, but forbearingly shunts philosophical discussion to the appendices of his measured biography. Hazlitt's unflinching directness helps Grayling keep emotion close to the surface. His most personal writing was his most public, full of fire and grudge, and his published work was his most confessional.

Coleridge told Hazlitt that he had guts in his brains. A dissenting childhood and education encouraged uncomfortably independent thought, which remained a touchstone whether in impassioned response to Edmund Kean's magnetic acting, which made his reputation as a critic, or in his unpopular lifelong advocacy of Napoleon. He became a star hack, but could not long toe the party line for any publication.

'I have never given the lie to my own soul,' claimed his last published essay: Hazlitt 'set out in life with the French Revolution' and clasped his principles close. He had an unforgiving eye for backsliders like Wordsworth and Coleridge, whom he had trudged 10 muddy miles to hear as a youth, but who later disappointed ('Alas! Frailty, thy name is Genius!'). His attacks on the poets were cruelly supported by close reading, though generous about their best work. In turn, Grayling amusingly tracks their elaborate tittle-tattle, slinging more dirt with each repetition.

A friend said he had never known Hazlitt out of love, but although he married two spirited women, he never achieved the relationship he idealised. Unusually sexually savvy in print - he caused outrage by insisting that Desdemona married Othello because she fancied him rotten - he yearned for a romantic, erotic and intellectual partnership. Too much reading, probably.