As an infant, Samuel Taylor Coleridge was acknowledged to be a prodigy. He was a brilliant schoolboy, of whom great things were expected. Those who encountered him as a young man recognized his exceptional gifts. 'STC' was an omnivorous reader, and a mesmerising talker on an astonishing range of topics. Ambitious schemes for literary, critical and philosophical works poured out of pocket. Nothing seemed beyond his powers. Plenty of people helped him, in various ways; two wealthy brothers provided him with an annuity, so that his genius need not be wasted on the mundane business of earning a living.

By the age of thirty, Coleridge had written the poems for which he is now remembered. But his career had begun to falter. A characteristic flaw was already apparent: the failure to finish anything. He seemed unable to resist the temptation to digress, to wander off his path into footnotes