We thought we would see the end of a world of boom and slump, sighs a character in JB Priestley's Time and the Conways, which opened at the National Theatre this week. Priestley was writing in 1937, but the topicality of such lines today – this one gets a loud ironic laugh from the 2009 audience – is one of the many reasons why his moment seems to have come again. When he went back to Bradford for the BBC in 1958, dubbing it a lost city that wasn't good enough for the people who lived in it, Priestley seemed out of kilter with the times as well as his birthplace. But he is too good a writer, in too many modes and mediums, to be overlooked for long. Now the 21st century is catching up with Priestley's preoccupations in ways that would have pleased this lifelong student of the disjunctions of time. After the revival of his plays, the rediscovery of his novels cannot be far away, while his social commentary and reporting remain models of clear English style. Priestley's work expresses a profound sense, well illustrated by Time and the Conways, that human beings should learn from their mistakes and do things differently. He was a founder both of the National Council for Civil Liberties (now Liberty) and of the Campaign for Nuclear Disarmament, as well as of the more short-lived Common Wealth movement, with its belief in cooperative socialist traditions. Like Keynes, Priestley has been rescued from comparative neglect by convulsive events. Their generation saw it first. They have much to teach our own.