Boswell's Presumptuous Task by Adam Sisman

It is such a good idea that you wonder why no one has not done it already: a biography of the greatest biography of all time. As Sisman notes, Boswell's Life of Johnson "stands next to other biographies as Shakespeare stands beside other playwrights". In exploring Boswell's struggle to realise his daring idea, Sisman lays plain the man himself: dissipated, sycophantic and erratic, but also determined, imaginative and irresistible. "He is so extraordinary a man," said Queen Charlotte, "that perhaps he will devise something extraordinary."

Boswell faced competition from nine other biographers including Mrs Thrale, who, much to his chagrin, was privy to far greater intimacies with Johnson. But the efforts of rival scribblers proved wanting while Boswell continued to beaver away at his 400,000-word epic. The effort wrecked both his career at the bar and his political aspirations. Like Johnson, he was absent from his wife's death bed. Both were wracked with guilt.

Sisman explores Boswell's techniques and sources – primarily his prodigious memory. Though Johnson and Boswell have been the subject of shelf upon shelf of fine books, Sisman's inspired addition ranks alongside the very best.