Ah, Wilderness! is the first of Eugene O’Neill’s plays that you’ve directed …

Yes, and there are so many I’d still like to direct – especially Long Day’s Journey Into Night. Ah, Wilderness! feels like a wonderful prelude to that play. There is a great resonance between the two plays, particularly as they’re both set in Monte Cristo cottage, Connecticut, where O’Neill grew up. Considering his father was an actor and they were always on the move, Monte Cristo (named after his father’s leading role) was the only place O’Neill ever really thought of as home. He returned to the cottage with his third wife, Carlotta, on Independence Day the year before he wrote the play – and 4 July is when Ah, Wilderness! takes place.

That visit prompted lots of memories about family and growing up, and a desire to rewrite his youth with a more aspirational version of his life – he’s projecting a more positive idea of what would have happened had he had a different upbringing, describing Ah, Wilderness! as “the way I would have liked my boyhood to have been”. Long Day’s Journey Into Night, by contrast, is the really visceral excoriation of his family – a far more truthful look at his childhood. Without Ah, Wilderness! he would not have been able to write Long Day’s Journey Into Night.

The play was written in 1932, but it looks back to an earlier era

O’Neill wrote it during the Great Depression. In 1933, when it was first performed, books were being burned in Germany – and the play probes the power of literature and what it can do to change the way you think. In his letters, O’Neill wrote about wanting to look back to 1906, a time before the first world war, a time when he believed there was a greater sense of the solidarity of the family unit, whereas everything felt more atomised for him in the 1930s – and this is a theme we can identify with now.

What relevance does the play have for today’s audiences?

Coming of age is a rite of passage we all experience and O’Neill captures the heady tailspin of these experiences through the character of Richard Miller who, at 17, is about the same age as O’Neill was in 1906. O’Neill is looking back 25 years and imagining that everything was better then and it’s the world today that is full of corruption and danger. But I think there’s a fallacy there – as a society we’re prone to idealise the past and think the world was a safer, better place once upon a time.

Essie, Richard’s mother, fears the books Richard has been secretly reading and the new ideas he may be exposed to – these anxieties have parallels with our contemporary fears about what our children have access to, via the internet. The power of the play lies in that fact that although it may be set in 1906, it probes the universal milestones of defining oneself as an adult.

The play captures that intense relationship you can have with literature during adolescence …

The play is set on Independence Day and looks at how Richard declares his own independence from his family. We follow Richard, hungry for new experiences, and see him discovering a sense of self-awareness and his beliefs. The play reminds us what it was like to be Richard’s age – discovering so many new worlds. I wanted to read English literature at university because I thought, “There’s only a finite number of experiences I can have as an individual. If I go and read novels for three years I can at least live vicariously through those characters.” Richard’s search for self-expression reveals he hasn’t found his own voice yet – he doesn’t know how to articulate his love for his sweetheart, Muriel, so he relies on poets such as Swinburne and Wilde. By the end of the play he starts to discover his own voice within his family and is reaccepted by them as an adult and finds ways to articulate his feelings and thoughts in his own words.

The title comes from the Rubáiyát of Omar Khayyám

Yes – I’ve just finished directing Happy Days for the second time and Winnie quotes from the same verse of the Rubáiyát that gives O’Neill’s play its title: “O, Wilderness were Paradise enow!” When her resources are diminished, Winnie finds succour by relying on the words and phrases of poets who have expressed her suffering. Winnie’s greatest fear is to be left alone in the “wilderness” and the title of O’Neill’s play captures that sense of the journey through the “wilderness” of our own lives. The Rubáiyát is an 11th-century Persian poem that was first published in translation in England in 1859, the same year as Darwin’s On the Origin of Species – and it captured the public’s imagination with its carpe-diem spirit. “Be happy for this moment. For this moment is your life,” it declares. It became the most influential poem of the early 20th century, with more quotes in the 1953 Oxford Book of Quotations than Shakespeare or the Bible.

Reading Ah, Wilderness! again after working on Happy Days, I understood more deeply Richard’s reliance on Khayyám and other poets and political writers to help him through the wilderness and to express the tumult of new emotions he is feeling.

What major changes have you made to the play?

O’Neill described the play as coming to him in a dream – he was struggling with another play, Days Without End, and then woke up with this play fully formed, title and all, and it “flowed out” of him. I want to re-create this dreamlike experience for the audience by editing the play so that it has no interval and they can be swept up in the dream of O’Neill’s world.

O’Neill called it an “American folk play” and that’s how we’re thinking of it. We’re trying to play the absolute reality of the characters and what’s happening in their lives, looking at their individual idiosyncrasies and all the family tensions. We’ve done this by setting up a lot of background improvisations to explore their interactions with each other. The play is set over the course of one Independence Day but we need to feel the impact of all the previous Independence Day suppers, all the old family wounds.

Our process has been about working in sketches and creating lots of character and scene studies that we can then develop into the performances. We’re discovering how our scenes speak to each other as we start to look at larger narrative sweeps. I love it when the playfulness of early improvisations is still present in the scripted scenes, so that once the text is learned, actors can play jazz riffs with the scenes and enjoy being playful.

O’Neill gives extremely precise stage directions and character descriptions. How much notice do you take of them?!

I love working with writers – I particularly like it when they’re alive and I can talk to them! When they’re not, then diaries, letters, annotated drafts and stage directions are all really helpful to get the clearest sense of what the playwright envisaged. It is, however, liberating to have a blank canvas to play with and so we have made a copy of the text for rehearsals that has no stage directions at all, not even entrances and exits. But then there’s our “bible” version of the script, too. Descriptions like “a wry smile” or indications of a particular action to perform, can be quite stymieing for a performer. But it can be interesting to go back and look at them and feel that we have O’Neill in the room with us. O’Neill describes Richard’s father, Nat, as “benignly ripened” when he comes home after having had several drinks while out with his brother-in-law Sid – and we’ve really enjoyed investigating that idea. O’Neill’s character descriptions are incredibly vivid and detailed because he really knew these people – often they’re composites of several individuals and so they’re very real to him and so he couldn’t help but describe them in forensic detail.

Our design process in relation to O’Neill’s very specific directions, for example, “furnished with scrupulous medium-priced tastelessness”, has been to abstract the world to evoke the notion of memory and the playwright going back to 1906 and trying to uncover and remember what life was like then, and what family relationships he wished he’d had. That allows it to be more resonant across time and help audiences relate their own relationships to the themes in the piece.

• 14 April to 23 May. Box office: 020-7922 2922. Venue: Young Vic, London.