"A man who writes to be read and not to be performed is no dramatist," said J.B.Priestley in a lecture published in 1957. In that same year, he penned a play that was destined - after brief airings in Canada and London - to be neither read nor performed in the ensuing half century. How lucky we are, then, that The Glass Cage should have been rescued from obscurity at last by the writer's son, Tom, and presented fresh as paint in a hugely entertaining production (director Laurie Sansom) at Northampton's Royal Theatre.

Presumably it was Priestley's very fecundity as a writer - so much else to focus on - that led to the neglect of this typically well-crafted and thought-provoking play. In it is presented a clash between old and young, between the staid attitudes of one generation - comfortable, complacent - and the very different views of their successors; more than that, we have a conflict of race and culture; and all of these contained in one family. They are the McBanes, members of a prosperous Toronto business dynasty headed by the Bible-bashing David (John Arthur) and containing his daughter Elspie (Natalie Burt), his easy-going bachelor brother Malcolm (Robert Demeger) and sister-in-law Mildred (Janice McKenzie). Irrupting into their quiet life come three figures from a very different world, the offspring of David's late brother Charles, a hard-drinking 'black sheep' who scandalised his brothers through marriage to a Native American, after which he headed north to expand (in fact lose) his fortune.

Shy at first, the trio quickly start to look like cuckoos in the nest. Lovely Jean (Rebecca Grant), a high-kicking chorus girl, soon catches the eye of Elspie's intended, trainee minister John Harvey (Peter Bramhill). Her intense elder brother Douglas (Dar Dash), meanwhile, reveals dark plans to share their uncles' fortune, while younger Angus (the excellent James Floyd, pictured) proves himself a true heir to his dad in hard drinking, as well as an imaginative user of tobacco (cigarettes up his nose!) and a most successful charmer of women (poor Elspie!).

But just as it seems that this superbly acted play is going firmly in one direction, the old stage magician Priestley swiftly conjures it somewhere quite different. You have until November 17 to see this most welcome not-to-be-missed revival (box office: 01604 624811 or www.royalandderngate.co.uk).