James Boswell was born in Edinburgh, the eldest son of a stern Scottish judge who wanted him to be a lawyer. Boswell did eventually become one, but what he really wanted was to be in London, among famous people, and to write down everything they said.

On May 16, 1763, in Thomas Davies’s bookshop in Covent Garden, he got his chance. Samuel Johnson, the great critic and author of the Dictionary, walked in. Boswell, knowing Johnson’s dislike of the Scots, blurted out, “Mr. Johnson, I do indeed come from Scotland, but I cannot help it.” Johnson replied: “That, Sir, I find, is what a very great many of your countrymen cannot help.” It was not a promising start, but Boswell went to visit him a few days later, and a friendship began that lasted the rest of Johnson’s life.

In between, Boswell traveled. On a grand tour of Europe he talked his way into meetings with both Rousseau and Voltaire, and he went to Corsica to meet Pasquale Paoli, who was leading the island’s fight for independence. His Account of Corsica (1768) made him famous, and for a while people called him “Corsica Boswell.” In 1773 he finally persuaded Johnson, then in his sixties, to tour the Highlands and the Hebrides with him, a journey both men wrote books about.

Boswell’s Life of Samuel Johnson came out in 1791, seven years after Johnson’s death. It was something new: a biography built from thousands of remembered conversations, in which you hear its subject think, joke, contradict himself and sulk. Boswell had a superb memory and the nerve to ask his friend almost anything.

The strangest part of his story came after his death. Boswell kept detailed private journals all his life, frank about his drinking, his gloom and his many love affairs, and they were long believed lost. In the twentieth century, great caches of them turned up in an Irish castle and a Scottish country house. When Boswell’s London Journal was published in 1950, it became a bestseller, and the great biographer turned out to be one of the great diarists too.