EUGENE O'Neill's autobiographical family drama Long Day's Journey Into Night is a classic of American theatre. Written in 1940, but not staged until 1956 (some three years after O'Neill's death), it burrows into the fractured heart of the family of Irish-American patriarch James Tyrone.

Tyrone is a classical actor who has wasted his talent on a mediocre play to which he bought the rights. Wealthy-but-miserly, his disappointment in his morphine-addicted wife, Mary, and his directionless, resentful sons, James and Edmund (who has tuberculosis), is matched only by his loathing of himself.

Directed deftly by Dominic Hill, this beautifully-weighted co-production between the Citizens Theatre and Home Manchester is as an archetypal play of two halves. The first half is a vivid sketch of the family's dysfunctions. The second, a turbulent reckoning in which hitherto suppressed and unspoken truths come explosively to the surface with an almost volcanic force.

The anguished truth telling between father and sons is enabled, to a very large degree, by alcohol. In fact, as in that other American classic, Edward Albee's Who's Afraid Of Virginia Woolf?, booze itself becomes a player in the drama.

The ever-superb George Costigan leads a universally excellent cast (which includes fine performances from Brid Ni Neachtain as Mary and Lorn MacDonald as Edmund). Costigan's Tyrone is every inch the bullish impostor, his bravado pulled so tight across his regrets that it has started to split. His speech about his childhood poverty, the Irish memory of famine and his terror of the poorhouse is simultaneously a cynical device to elicit sympathy and a deep-seated fear dragged up from the depths of his soul.

Tom Piper's set (which is lit intelligently by Ben Ormerod) is largely constructed of transparent plastic sheeting. It is recognisably domestic nonetheless, and succeeds in being simultaneously functional and symbolic.

If O'Neill's play is a classic in the world theatrical canon, Stephen Greenhorn's Passing Places holds a more modest, but nevertheless enduring, place in the affections of Scotland's theatre lovers. First staged, at the Traverse Theatre in Edinburgh, in 1997 this evocative and comic "road movie for the stage" is deserving of this Dundee Rep revival.

The play follows working-class Motherwell youths Alex and Brian who, being understandably restless, nick a surfboard from the sports shop where Alex works and head for the surfers' Mecca of Thurso. Unbeknown to them, the board is valued by Alex's crazy, gangster boss Binks way beyond its price tag.

As the lads meander through the Scottish Highlands, "finding" themselves a la George Harrison in 1960s India, Binks is in hot pursuit on his motorbike.

Director Andrew Panton's production achieves the crucial sense of momentum, a fact that owes a great deal to the live music and the sprightliness of the cast. There is a constant sense of energetic movement on and around designer Becky Minto's deceptively versatile set (which is dominated by a boldly envisioned road that winds backwards from the front of the stage and up the back wall).

On their travels, the guys meet, among others, Mirren (Eleanor House on wonderfully engaging form), a young, Highland lass who is lucky enough to have been named after the runaway winners of the 2017-18 Scottish Championship by her football mad, Paisley-born father. John Kielty illuminates a variedly accomplished cast, playing a series of comic characters of both sexes with Pythonesque brilliance.

Barrie Hunter is gloriously bonkers as Binks, while Ewan Donald (Alex) and Martin Quinn (Brian) play the urban misfits with a winning combination of humour, bitterness and pathos.

Greenhorn's play may have stood the test of time, but I confess to being doubtful as to the durability of Frances Poet's latest drama Gut. Co-produced by the Traverse and the National Theatre of Scotland, the play is a coming together of two subjects that are very much in the current frame of the British mass media (namely, paedophilia and mental distress).

The piece plays strongly to those who demand that new theatre works should, first-and-foremost, be socially and politically "relevant". Not for the first time did I find myself watching a new play and wishing that the latest generation of Scottish playwrights could be locked away for a year, with no access to the news or social media, in a library that holds only the classics of world theatre and poetry.

Which is not to say that the drama, in which young mother Maddy's anxiety about "stranger danger" descends into a catastrophic meltdown in her mental health, is a bad play. Although it is tilted too heavily towards the banalities of everyday speech, the piece has a stronger emotional drive and a smarter sense of dramatic structure (no doubt assisted by the nuanced directing of Zinnie Harris) than most new plays.

This said, the work is constrained by its naturalism. Despite strong performances across the piece, one can't help but feel the absence of a real, psychological undertow.

Like a soap opera, the drama seems overloaded with events, but lacking in depth. The exception to this is in the writing of the strangers, all of whom are performed with compelling brilliance by George Anton (who plays the characters, not as themselves, but with the underlying menace that is manifested in Maddy's mind).

New theatre writing is devilishly difficult to pull off. Although it is not without qualities, I suspect Gut will prove to be another also ran in the annals of Scotland's live drama.