THIS year marks the 25th anniversary of the death of Tennessee Williams, one of the greatest of all 20th century playwrights; and it's hardly surprising that the 2008 Glasgay! Festival has seized the opportunity to mount a major celebration of Williams's work, from the iconic film versions of great plays like A Streetcar Named Desire and Cat On A Hot Tin Roof, to studio theatres crammed with rare productions of his short plays and fragments. Williams's career, after all, spanned the years from the early 1930s – when the sexuality he shared with millions of men could barely be mentioned in public, except through strained heterosexual metaphor – to the 1980s, when he was surrounded by a new generation of "out and proud" gay writers. And during all that time – in plays such as Cat On A Hot Tin Roof, first seen in the early 1950s – he pushed hard at the boundaries of public debate on sexuality, raising the issue with a frankness often suppressed in the film versions of his work.

Williams's The Parade – first written as early as 1940, never performed until 2006, and now presented by Laurance Rudic at the Citizens' – is a short 70-minute piece on which Williams worked throughout his life, and which in some ways perfectly captures his sense of a sexual life lived in limbo between changing worlds. Based on an early failed summer romance, the play shows three people on a beach, contemplating the coming end of summer. Don is a writer in early middle age, passionately in love with a beautiful, indifferent young beach bum, Rich; Miriam is a wealthy young woman who loves Don, but cannot draw him away from his obsession, or spare him the pain of it.

The Parade is not a likeable play. Don is a classic self-obsessed artist, simultaneously self-hating and self-pitying. Rich is an egotistical young oaf, apparently incapable of honest desire; Miriam talks more sense, but never gets up and walks away when she should. And none of this is made less irritating by the soporific pace of Rudic's production, or the long, diva-like pauses that punctuate his own performance as Don. There is, though, something timeless and compelling about the sad triangle of unfulfilled yearning formed by these three, as the sound of the waves rolls endlessly on the beach; and Adrienne Zitt and Alex Harries turn in impressive performances as Miriam and Rich, young, strong, sensual, and intensely physical.

There's something much more attractive about the older Tennessee Williams revealed in The Chalky White Substance and The Municipal Abattoir, two tiny 20-minute fragments written towards the end of his life, and now given a sharp production at the Arches by Drew Taylor and young team of recent RSAMD graduates. In both plays, the focus has shifted from issues of sexuality towards the idea of authoritarian government, and of the suppression of human freedom through fear.

The Chalky White Substance is a dialogue between a young man and his older male lover and "protector", set in a future world devastated by war, where the environment is crumbling to dust, women are sick and scarce, men use one another for sex, and everyone is increasingly brutalised by fear of a totalitarian regime. The Municipal Abattoir is a straightforward political encounter between a young freedom-fighter, and an older man so browbeaten by a fascistic government that he is on his way to turn himself in for extermination at the local abattoir, after being denounced by telephone.

There's a strong, haunting, yet unobtrusive design by Susan Kirkwood and the company, all dust-sheets covering the last remnants of a shattered civilisation; and a couple of tightly-focused performances from David Ashwood and Mark Kydd as the younger man and the older. And it's tremendously rewarding to be reminded that for Williams, the struggle was all about freedom; including not only the hard-won freedom to express your own sexuality, but also the whole related range of fundamental freedoms threatened by those who would seek to control the minds and lives of others.

If Tennessee Williams was both passionate freedom-fighter and fading southern belle, though, it's the sad southern belle who predominates in Barry Henderson's A Slow Dissolve, a gentle 40-minute meditation on what Williams's writing means to a fragile contemporary gay man slowly recovering – or not – from a broken love affair. Henderson's particular obsession is Williams's greatest play, A Streetcar Named Desire, and the image of its heroine, Blanche Dubois. Traumatised by a tragic past, dismissed from her teaching job for sexual misdemeanours, poised on the edge of madness and old age, and famously dependent on "the kindness of strangers", Blanche has been an icon for the vulnerable, the rejected and the emotionally shipwrecked ever since she first appeared on stage in 1947; and Henderson brings a lovely, wry intelligence and openness to his account of her story, intercut with fragments from his own life in contemporary Glasgow. But I have a feeling that if Williams was around today, he might want to pass on a rousing reminder that he created not only the tragic Blanche, but also Maggie the Cat, the feisty heroine of Cat On A Hot Tin Roof, the never-say-die fighter for life and love who knows what she wants, and who will not be defeated in her struggle to get it, come what may.

&149 The Parade until 1 November; The Chalky White Substance and The Municipal Abattoir until 25 September; A Slow Dissolve, run ended.