THEATRE / Centre stage for activist's elegy: A Scots Quair - Assembly Hall: Night After Night - Traverse; The Legend of St Julian - Traverse

SPEAKING AS one with a long accumulated prejudice against Edinburgh's Assembly Hall, particularly when its pews echo to works of local interest, I have to salute Lewis Grassic Gibbon's A Scots Quair. The trilogy (adapted by Alastair Cording) spreads through the printed programme like an immovable rain cloud, but it's a major achievement by Glasgow's TAG Theatre Company and the star event so far among the festival's official offerings.

Gibbon (born James Mitchell), a Communist from Scotland's rural north-east who got out at the first opportunity and celebrated his austere homeland from the fleshpots of Welwyn Garden City, has been claimed by some as a prose MacDiarmid. The three novels that make up A Scots Quair - Sunset Song, Cloud Howe and Grey Granite - appeared shortly before his early death in 1935. They centre on the character of Chris Guthrie, from her childhood in a crofting family before the First World War through to the depression in industrial Scotland.

There is a sentence to make your eyes glaze over] Yes, you can see a lot of it coming. Yes, Chris does have a Bible-mad father and a long-suffering mother whose death thwarts her hopes of going to college; her first husband is killed in the war, and her son joins the CP as a strike-leader. There is a lot of preaching. However, in Scotland as anywhere else, most people do lead typical lives; and one of Gibbon's main points is that they are fooling themselves if they pretend not to be products of their place and time. The trick, as seen in Tony Graham and Andy Howitt's production, is to turn a familiar route into a voyage of discovery.

The trick is not complete. Gibbon's heroine has been claimed as one of the great female characters of Scottish fiction, but as Pauline Knowles plays her - impassively submitting to circumstance and preserving the same scrubbed virginal appearance over 25 years - she hardly exists. But the life surrounding this dead centre is enthralling. At first all you register is the village gossip, seasonal festivities, courtship dances and family conflicts, all richly coloured by actors including the dangerous Michael Mackenzie and Jacqueline Anderson, who has the sharp features and darting energy of a female Puck. Then, as the outer world begins to impinge, a larger pattern takes shape, and the very landscape becomes politicised in symbolic cloud formations (represented in the irridescent silk banner overhanging Sally Jacobs's set), open-air meetings and reflective songs. From its obscure base, the show expands to reflect the history of modern Europe, including police brutality and colonialism. Satires on English newsreaders and visiting dignitaries are viciously funny, and spot-on; and by the third play you are half-agreeing with Gibbon that English words 'could never say anything that was worth the saying'.

Meanwhile, the music grows increasingly insistent: an authentic folk sound of flutes and tin whistles over a drone bass, which continues from croft to steel mill and finally summons Chris back to her birthplace - by which time you recognise it as the defining element of Gibbon's work. It's an activist's elegy, simultaneously declaring that change must come and that nothing changes.

To hail this as a star event is no great claim in view of the week's other official show: Peter Sellars' Salzburg Festival production of The Persians, which has now finished its run at the Lyceum, having broken all records for crimes against the classics in the name of topical relevance. Aeschylus' tragedy famously dramatises the Athenian victory at Salamis through the mind of the defeated enemy. Sellars and his adapter, Robert Auletta, saw in this a parallel with the Gulf war and set out to perform a similar operation on behalf of the Iraqis and their leader.

As soon as you line up the two subjects it is obvious that their details do not fit; but, intoxicated with their idea, the collaborators plunge blindly into the quagmire - identifying the ominously expectant Persian capital with a Baghdad where the bombs are already raining down, and the ignominiously vanquished Xerxes with the defiantly surviving Saddam. Worse than this: Auletta, while preserving the Aeschylean outline and characters, has rewritten the dialogue. Athens, it emerges, was after Persia's oil reserves; and Xerxes stood no chance against all that Greek technology (no word on the technology with which Sellars turns this under-designed, six-character show into an ear-blasting ordeal).

The shade of Darius rises from Hades and makes a fact-finding tour of the capital's hospitals, accompanied by Queen Atossa, who insists she has always loved him despite his failure to get along with young Xerxes. So that is why the Kurds and Marsh Arabs have to bleed: to sate Saddam's Oedipus complex. Enter the war-torn Xerxes (John Ortiz) declaring that defeat is victory, until Atossa quells him with a mother's smile: 'Xerxes, let's go change your clothes.' If anything were needed to prove American incomprehension of anything outside America it is this dire charade.

Two Traverse Theatre recommendations. The Legend of St Julian, devised by the Communicado company from Flaubert's story, brings no fresh insight to this repellent fable of a parent-slaying hunter who achieves salvation by embracing a leper. But in Gerry Mulgrew's production, coupling inventive grace with exquisite visual transformations, it conveys the sense of a stained-glass window stirring to life. Night After Night, another musical from the partnership of Neil Bartlett and Nicolas Bloomfield, is that great rarity: a successful theatre piece about life in the theatre. Beginning in 1958 with Bartlett playing his own father taking his girl out for a show, it develops into a revue-like survey of the homosexuals who kept the stage running during the boy-meets-girl era. The company doubles as theatre staff and chorus boys, and involves Bartlett senior in the act (the only narrative mistake).

It is a show about dreams and the tough business of keeping them alive among an inward-looking community for whom the past exists only as a string of hits. For all its defiant triviality, the emotional range is wide: not least in the numbers which extend from pastiche romantic ballads for public consumption to the raunchy desperation of 'Tell Me How You'd Like Me to Be', where the company ransack the wardrobe in their hunger for acceptance at any price. Not to be missed.

'A Scots Quair', Assembly Hall, 031-225 5756. 'Night After Night', Traverse, 031-228 1404. 'The Legend of St Julian', Traverse.