Philip Roth is a writer who speaks his mind - and rarely runs out of things worth saying

Sarah Churchwell on a giant of American letters, 83 today

Philip Roth at his desk in the Yaddo artist' retreat in 1968 (Getty Images)

At one point in Philip Roth's novel Operation Shylock, a novelist named Philip Roth who has come to Jerusalem to confront an impostor who claims to be Philip Roth declares: "Everything dictated silence and self-control but I couldn't restrain myself and spoke my mind." Over nearly 50 years as a novelist Roth has earned a deserved reputation as a writer who speaks his mind – a mind that rarely runs out of things worth saying.

Most of his fiction is narrated through an array of alter egos, including Alex Portnoy, David Kepesh, Peter Tarnopol, Mickey Sabbath, and, most famously, Nathan Zuckerman. The writer Philip Roth, the protagonist of five books, is no more – or less – recognisably autobiographical than any of his other counterfeit selves. "I can only exhibit myself in disguise. All my audacity derives from masks," Zuckerman declares in The Counterlife, a metafictional tour de force exploring self-division and the unlived life – a great theme of Henry James, one of the writers to whom Roth most often pays tribute.

Having apparently slowed down with age, Roth surprised everyone with an autumn flowering in the late 1990s, publishing his so-called "American Trilogy" – American Pastoral, I Married A Communist, and The Human Stain. In 2004, he published The Plot Against America, a counterfactual history that imagined what would have happened to the US if the antisemitic Charles Lindbergh had defeated Franklin Delano Roosevelt in 1940. The America that is flirting with electing Donald Trump as president sounds suspiciously like one that Roth might have invented, and then deliriously, furiously, railed against. If only it was just a Roth fiction.

Sarah Churchwell is Chair of Public Understanding of the Humanities and Professorial Fellow in American literature at the School of Advanced Study, University of London