The Lady from Dubuque, Theatre Royal Haymarket, London Sizwe Banzi is Dead, NT Lyttelton, London Dying For It, Almeida, London

Maggie Smith is a mystery. She is the titular intruder in The Lady from Dubuque, materialising in Sam and Jo's chic yet troubled marital home in Connecticut. Who she really is remains hazy in this warped domestic nightmare by Edward Albee - written in the late Seventies but only now receiving its West End premiere, directed by Anthony Page.

Smith is elegantly skeletal in a funereal black dress and choker of pearls, quietly overpowering, subtly sardonic - with just a flicker of a raised eyebrow as she reclines on the sofa. She surely doesn't hail from a farm in Iowa. Yet that is what she claims, insisting she is the mother of Catherine McCormack's Jo, come to comfort her in the throes of a terminal disease. Robert Sella's Sam is enraged because he knows she is lying. Or has Jo fibbed about her estranged parent? Or is Sam so grief-stricken that he's hallucinating? Maybe the lady from Dubuque is ultimately the angel of death.

Alas, none of this is as intriguing as it sounds. Before Smith arrives, we have to endure a protracted drinks party. This is wearisomely like Who's Afraid of Virginia Woolf? with McCormack being unbelievably bilious. The party game of Twenty Questions also underlines the notionally profound question "Who am I?" without truly touching a nerve. Asides to the audience seem a mere gimmick and the intruders are Pinteresque.

Smith hovers effortlessly between the sinister and the comically crisp. Peter Francis James is also a droll, unsettling Oscar - Smith's black beau-cum-henchman who mocks bigoted whites by flicking between debonair chit-chat, caricatured African-American patter and serious violence. However, this piece feels flimsy. Why it closed after only a few performances on Broadway is no longer a mystery.

In Sizwe Banzi is Dead, the question of "Who am I?" is explored far more engagingly. This historically influential, anti-Apartheid two-hander is being performed, one last time, by the celebrated black South African actors, John Kani and Winston Ntshona, who co-devised it with Athol Fugard in 1972. Unlike Albee's Jo, Ntshona's Banzi wants to survive. A poor migrant worker faced with a damning authoritarian stamp in his passbook, he finally gains a new lease of life by adopting the identity of a dead man. He is helped by a pragmatic township comrade, Kani's Buntu. This is framed by scenes featuring another entrepreneur, Styles (also Kani), who chuckles about his former job at the racist Ford car factory and proudly tells how he set up his own photography studio. Then he encourages Sizwe to play out his own dreams of a better life, in snapshots.

This production goes slack in one long drunken scene where the veteran Ntshona is underpowered. Nonetheless, he is an endearing clown, acting the simpleton with his head poking out of an outsized suit like a tortoise, cracking a slow smile. Meanwhile Kani is full of vigour, warmth and joyous playfulness, morphing into multiple characters. It's not only an amazingly good-humoured history lesson, but also thought-provoking for us today, dealing with immigration, identity cards and the idea that you can escape thankless jobs by reinventing yourself.

Last but not least, the revival of Nikolai Erdman's banned anti-Stalinist satire Dying for It (or The Suicide) proves a startling hoot, wildly combining farce with serious undercurrents of political discontent. Semyon is a starving prole, so wretched that he declares he will blow his brains out. Half his fellow-citizens then egg him on, each asking him to put a different spin on his death so it will serve their particular cause - Communism, the Church, romantic love etc. These constructed truths are, so to speak, their propagandist attempts on his life.

Moira Buffini's English adaptation is vibrantly funny and brings home how bold Erdman was, giving the Kremlin such cheek that - and this is the real tragedy - he was exiled to Siberia. Rushing around beautifully dilapidated staircases and balconies, Anna Mackmin's cast are exuberant. Tom Brooke is hilariously manic as Semyon, stringy and squiffy-faced with his hair on end, like Stan Laurel put through a mangle. Ronan Vibert is a superbly devilish member of the intelligentsia, and Liz White shines as Semyon's sweetly loving but exasperated wife. Highly recommended.

k.bassett@independent.co.uk

'The Lady From Dubuque' (0870 400 0626) to 9 June; 'Sizwe Banzi is Dead' (0870 040 0046) to 4 April; 'Dying For It' (020 7359 4404) to 28 April