The fifth shortlisted group is the Red Deer Readers in Sheffield, another mixed-sex group who have been meeting for eight years and has produced its own website for other reading groups to use.However, the final group is all-female, the Isle of Islay Book Group in the Hebrides whose members write a regular book review column for their local newspaper and read contemporary Scottish literature.Professor Jenny Hartley, who has researched reading groups and was one of the judges, said: "This year's shortlist overturns the popular preconception that reading groups are a relatively recent phenomenon dominated by women."The shortlist is remarkable for its diversity. Ms Dixon said: "We do read other books but specifically we read black authors because black authors aren't widely known in our society." It has just completed Purple Hibiscus, the Orange Prize-shortlisted first novel by the young Nigerian author, Chimamanda Ngozi Adichie. It is also thought to be the first book club in the country to produce its own book, a collection of prose and poetry from its members. The Black Reading Group in Walsall was set up five years ago at the central library by a librarian, Sonia Dixon, as part of Black History Month celebrations. Yet the other contenders on the shortlist for the top prize of a visit to the Edinburgh Book Festival next month also disprove the popular conception of book clubs as a women-only affair.An all-male prisoner reading group at High Down prison in Surrey has been shortlisted for the prize after one group member described it as "a breath of fresh air; a monthly release when close to despair".Were they to win, however, they would not be allowed out to Scotland but an alternative prize - probably a visit from an author - would be arranged.And two of the other contenders are mixed-sex groups. It now has 45 members of different ethnic backgrounds with an age span of nine to 70 and focuses on reading black history and black authors. Reading groups may have hit the national headlines when Channel 4 produced its drama, Book Club, and Richard and Judy introduced their summer selection of good reads.

But any suggestion that they are a recent phenomenon was disproved yesterday when two groups that have met for 30 years or more were shortlisted for the fourth Penguin/Orange Reading Group Prize, organised in association with Ottakar's bookstores. The Congleton NWR (National Women's Register) Book Group in Cheshire has read more than 300 books since it was founded 31 years ago while the Crosby Reading Group in Liverpool began as an off-shoot of the National Housewives Register, a discussion forum, and has met for 30 years.Both are all-female. Next to him, a now beaming Jocasta jigged up and down to the beat And in his grave, Sophocles, too, was turning wildly. It came at the curtain call, when, in the style of a West End musical, the principals reprised one of the numbers. It was the song about the prophecy that Oedipus would kill his father. There at the front of the stage was a still-bloodied Oedipus grooving for all he was worth. He was also a little old for the part, being in his late forties, but was a powerful presence, and his direction was often gripping.

When the blind priest Tiresias, his face the shocking white of a clown's, leapt out of his wheelchair and crawled across the stage, arms flapping like wings, to tell Oedipus the truth, it wasn't just compelling, it was terrifying.Even if you know the story, it is asking a lot for tourists to follow two-and-a-half hours of Greek. Some 30 per cent of the audience now come from outside Greece, and offering a translation, whether by surtitles or headsets, should be considered. But even without translation, this is a great theatrical experience.So, what stopped this absorbing evening from getting five stars? The answer is, one of the most bizarrely inappropriate moments I have ever seen at the theatre. And the performance, with its challenging mixture of traditional and modern, certainly didn't please all the Greeks in the audience But I found it thrilling. Sophocles' version of the Oedipus story was acted out in conventional form, but the chorus sang their words to the music of the Bosnian film composer Goran Bregovic, accompanied by a band.Yorgos Kimoulis, who played Oedipus, was also the director, a dual role not always to be recommended.