Others have studiously kept their lives and literature apart. The two most famous facts we know about Wallace Stevens are that he wrote lyrical neo-Romantic poetry and that he was an insurance lawyer, and never the twain shall meet. Shakespeare’s biographers have concluded, serially, that he was an upwardly ambitious and shrewd businessman, shamelessly sycophantic to the rich; or an obese, syphilitic homosexual; or a genteel and witty American patrician: take your pick. Such examples block the impulse of readers and writers of the popular genre, ‘literary biography’, to ask the intriguing question: where in those lives did the literature come from?

If anybody invented the ‘literary life’, it was Samuel Taylor Coleridge (1772–1834). His Biographia Literaria (1817) translates into exactly this phrase. But like everything else in his life, as his latest biographer, William Christie, helps us to understand, Coleridge insisted on taking the notion at its most complex possible level. His account gives us little of everyday factuality, revealing virtually nothing about the kinds of things biographers usually want to know. In that sense, his friend and early collaborator William Wordsworth, in The Prelude (1805), subtitled ‘the Growth of a Poet’s Mind’, is much more informative, even if Wordsworth continually revised the ‘facts’ as he went through life. Instead, Coleridge gives us an ambitious philosophical and psychological disquisition on where ideas and identity come from, impenetrable to all but trained literary historians.

His father, who had indulged every whim of the prodigious child, died when Coleridge was eight, leaving his son with a whopping intellectual self-esteem bordering on arrogance, and also a lifelong void to be filled, as Christie surmises, by a series of surrogate father-figures. His mother, apparently in awe of her son’s intellectual precocity, left him to boarding school, relatives and his own devices, perhaps contributing to his later mistrust and aversion for domestic women, alongside an equal emotional void and a longing for female, suitably intellectual companionship.

Romantic poets had a habit of dying young. Chatterton died at seventeen, Keats at twenty-five, Shelley at thirty, Byron at thirty-six. Most lovers of their poetry, at some stage, speculate how their lives would have unfurled if they had lived longer. The reverse speculation is equally inviting. How would a poet be regarded now if he had died young? Wordsworth, who lived to eighty, would have a reputation more or less opposite to the one he holds. He would be seen as a political radical who went to France to support the Revolution, fathered an illegitimate child in France to Annette Vallon, and wrote poems such as ‘Descriptive Sketches’ and ‘Guilt and Sorrow’, poems which there are ‘none to praise / And very few to love’. Blake, who was born before the lot of them and survived most, would have still held the same reputation, since his radical views on politics, poetry, sexuality and culture deepened but did not alter during his lifetime, and his monogamous attachment and artisan’s routine never varied.

The oddest case would be Samuel Taylor Coleridge. If Coleridge had died in 1797, at twenty-five, he would later have been readily accepted by students in the 1960s as their truest role model, in place of Blake. As radical as anybody in England at the time, he zealously espoused the democratic ideals of the French Revolution and planned to practise in America a brand of utopian anarchism which he named Pantisocracy. Known as a firebrand and mass orator, he gave public lectures on politics and literature that attracted opprobrium from Tory reviewers and the admiration of radicals. He was known to be a philosopher translating and researching the German avant-garde thinkers, again almost a badge of authenticity for the 1960s student. He took opium, originally as a painkiller but also as a ‘recreational’ support, and at the time welcomed the opening of ‘the doors of perception’ it brought. Notoriously, a laudanum dream inspired the greatest drug poem ever written, ‘Kubla Khan’ (it is a shame that the man from Porlock who called on business and interrupted the reverie, never existed, and seems to have been invented by Coleridge because he was later embarrassed by the fragmentary state of the poem). By the time he was twenty-five, Coleridge had written virtually all his poems we now value, and especially that extraordinary work with its profound anticipations of modern psychiatry, ‘The Ancient Mariner’. He had single-handedly innovated a new form of poetry, the conversation poem, which provided him with the perfect vehicle for his manic depressive personality and for his brilliantly associative, conversational manner (monologues), which would in a later age have been hailed as performance poetry.

Hailed by everybody who met him as ‘wonderful’, ‘STC’ was expected to lead an extraordinary literary life with no bounds. While not so mad, bad and dangerous to know as Lord Byron, it could plausibly be intoned of the charismatic and iconoclastic Coleridge in 1797: ‘And all should cry, Beware! Beware! / His flashing eyes, his floating hair!’ In fact, however, Coleridge lived on for another thirty-seven years, and his life did not so much unfurl as unravel. Biographers tacitly tell the story even through the structure of their works. The doyen of Romantic biographers, Richard Holmes, wrote an impassioned account of The Early Years as a first volume of Coleridge’s life (1989), climaxing when his subject was thirty-one, but it took him nine years and much anguished labour finally to complete Darker Reflections (1998). William Christie, in this admirably succinct single volume, spends about 120 pages detailing the events up to the ‘annus mirabilis’ of 1797, then only sixty pages on the next decade, and thirty on the next thirty years.

A similar story emerges from accounts by contemporaries. The true radical, John Thelwall, had from the beginning suspected that his friend’s political beliefs and intellect were as threadbare as his clothes, seeing even in Coleridge’s early writings on religion, ‘the very acme of abstruse, metaphysical, mystical [sic] rant’. Others, like William Hazlitt, who began as admirers, gradually noticed to their dismay the radical’s decline into a conservative apologist for the Anglican church and the English conservative party, and a writer far more abstrusely prosaic than poetic. Wordsworth, who had benefited so much from Coleridge’s poetic theorising and given so much to his friend’s welfare, was finally reported back to Coleridge (perhaps inaccurately) as having ‘no Hope’ of the man, expostulating that he had ‘for years passed … been an absolute nuisance in the family’. A helpless drug addict who screamed in his sleep and suffered from a range of related ailments, such as chronic constipation; short, obese and ridiculously ‘powdered’; condemned as plagiarising from the very German philosophers he had celebrated, emotionally (and sometimes financially) exploitative of friends and new acquaintances; deracinated mainly in a lifelong flight from a wife whom he despised for what he saw as her intellectual inferiority (while still dreaming with infantile jealousy of other women): Coleridge lived to be a wreck.

Whether we see him as a 1960s student before his time, or a spectral premonition of what the 1960s man would live to become after leaving university, Coleridge at the very least stretches the tolerance of any biographer. In a curious way, the biographer takes on almost precisely the role inflicted on Coleridge’s long-suffering friends, those like Lamb and Crabb Robinson and even the Wordsworths, who maintained some residual faith in him through the long, distressing and painful journey of his later life.

In chronicling such a ‘damaged archangel’, ‘faith’ is indeed the right word. Christie is an exemplary companion, both for Coleridge and his readers, maintaining throughout a cheerful indulgence, tracing the suicidally depressive troughs with gentle reminders that Coleridge somehow needed to face the very worst before he could revive self-belief, and reserving a sceptical distance even in the eddies of manically sustained activity. And astonishingly, the whirlwind activity continued. Whether he was editing a journal, writing on theology, planning impossibly large ventures, or simply reflecting on his own intellectual life, Coleridge continued with his schemes and his dreams, infecting others with his enthusiasm until they lost patience.

The enigma is that it would be a mistake to say simply that he ‘declined’, since in many ways he did not, either in his output or energy. It is also wrong to dismiss his later work as somehow ‘misguided’, since his brief shafts of insight show that Coleridge was already probing the very contradictions and psychological complexities in Romanticism which would take almost two centuries to mutate into the fissures and fragments of postmodernism. The questions he was asking were long before their time, and the tragedy may have been the fact that a language was not available to him in his quest to answer them, and that the failure to answer caused him the severe psychic pain later to be known as existentialism. ‘The Ancient Mariner’, indeed, is existentialism’s classic statement, as ‘Kubla Khan’ is the counterculture’s, while his probing of the ‘EGO’ and its shadow, the imagination, are Freudian a century before Freud.

Coleridge’s own cri de coeur – ‘No one on earth has ever LOVED me’ – was extraordinarily ungrateful to the long line of friends and biographers who have found him fatally entrancing, but who end up confessing that nobody could unconditionally love such a man in the way he wanted, or enough to satisfy his insatiable demands and to abide his insufferable ways. All these things Christie anatomises and confesses, but he keeps us reading to the end, to see where the ‘wonderful’ Coleridge had come from, and where he was to go.