Howard Katz, Royal National Theatre, London;<br></br>Streetcar To Tennessee, Young Vic, London; <br></br>Woman in Waiting, New Ambassadors, London

Why watching men fail makes bad drama

His bubble has burst. That's the awful truth facing Howard Katz, formerly successful showbiz agent and eponymous hero of Patrick Marber's new would-be tragedy at the National's Cottesloe Theatre. We see Ron Cook's haggard Katz brazenly wheeling and dealing but underneath he's having a mid-life breakdown because he no longer believes in anything.

At the office, in exaggerated satirical scenes, he wildly insults swanky TV execs while at home, more sadly, he irrevocably hurts his well-meaning wife and father, Jo. Losing everything, he ends up a suicidal tramp.

On one level, Marber is boldly ambitious, inviting you to see Katz as his answer to the ranting homeless Lear of contemporary London and shouldering big issues including modern cynicism and the need for faith. Katz, a lapsed Jew, ultimately prays, declaring: "I want to live. Tell me how to live."

Nonetheless, Marber's own glittering career takes a tumble here. Katz's climactic speeches sound bald and engineered. Marber's previous NT hit Closer had a sexually charged plot to conceal such flaws. Here Cook is doing his best to be poignant, switching between bullishness and welling tears. Yet his character's descent from riches to rags is string of unconvincing vignettes ­ supposedly memories flashing though Katz's mind.

Designer Rob Howell's revolving stage can suggest swirling hallucinations and Trevor Peacock is wonderfully craggy and tender as Jo. But other members of Marber's cast are dismally stilted.

At the Young Vic Studio more souls are yearning to escape disappointing lives in Streetcar To Tennessee. This is a clutch of early shorts by Tennessee Williams, strung together by Timothy Sheader.

In This Property Is Condemned, a psychologically wobbly gal called Willie ­ eccentrically dressed up in a chiffon ­ lives in a tumbledown house and fancies she's besieged by beaux. Next in Talk To Me Like The Rain And Let Me Listen (which lasts slightly longer than its title), a young wife is cracking up in a city tenement. Later, in Moony's Kid Don't Cry, it's a husband who's desperate to flee. In between, The Dark Room is a dialogue between a scandalised social worker and a shrugging single mother. And finally in Hello from Bertha, a hallucinating old woman, kicked out of her bedsit, wishes she were back with her long-lost lover.

These are rarely staged plays and you can see the seeds of Williams' greater works, Willie most obviously being a fledgling Blanche DuBois. These portraits of impoverished and stressed lives also notably preempt John Osborne's Look Back In Anger (1956) by over a decade.

However, Sheader's production lacks polish. Scrawny Lisé Stevenson acts anguish with intensity but is regrettably joined with emotionally limp John Marquez and too many speeches are mumbled or hollered. Really Williams' playlets are just apprentice sketches too and his recurrent theme of mental instability ­ though sadly related to his own family's troubles ­ starts to feel like a narrow obsession.

By contrast, black South African actress Thembi Mtshali has moved on from a wounding past. Playing at the New Ambassadors, A Woman In Waiting is an autobiographical solo show that should, by rights, be gruelling. Under apartheid, Mtshali's mother had to slave as a domestic for a demeaning white master, leaving her no time to raise her children. Then history repeated itself when Mtshali was obliged to labour as washerwoman whilst desperately missing her new-born baby.

Happily, Mtshali went on to become a celebrated international actress who is now rediscovering her traditional culture. Woman In Waiting, very simply staged, interweaves inventive mime, storytelling and song and brims with humour.

'Howard Katz': RNT, SE1 (020 7452 3000) to 28 July; 'Streetcar To Tennessee': Young Vic, SE1 (020 7928 6363) to 30 June; 'A Woman In Waiting': New Ambassadors, WC2 (020 7369 1761) to 30 June