In book form, Eugene O’Neill’s play “Long Day’s Journey into Night” has the feel of a novel. Unlike Shakespeare, who almost never offers stage or extended character notes, O’Neill gives more than a dozen paragraphs of introductory material before the opening scene of Act I – the titles of books on the shelf, the length of a nose, the resonance of a voice. He inserts such details at the beginning of each scene and often in the midst of a scene. It is the hallmark of a form he shaped in American theater: the literary play.

For this reason, I often prefer to read O’Neill than to see the works staged. But also for this reason, I am impressed and intrigued when a theater is courageous enough to mount a play by O’Neill, whose heady, hard-emotion dramas won him four Pulitzer Prizes and made him the first and only American playwright to win the Nobel Prize.

Last weekend, Penobscot Theatre Company opened “Long Day’s Journey into Night” under the direction of Chris Dolman, best remembered locally for “Jack and Jill” and “Art.” The production was long – close to four hours – and the actors had not quite reached their stride with the rambling monologues that fill each of the four acts. The performers started at a high pitch and had battered each other to a pulp by the end. The audience was small and enthusiastic, though a few left at intermission probably because of the intimations of a snowstorm that night, but possibly because this is exhausting theater.

“Long Day’s Journey” is a depressing play about embittered theater family members who are either morphine addicts or alcoholics, has-beens or wannabes, pitifully sacrificing or pitilessly sacrificed. While O’Neill doesn’t seem to judge them, he also does not elevate any one of them – even the maid – to the level of moral superiority.

The themes of play come largely from O’Neill’s own family life. He was born in 1888 in a hotel room in New York City, where his father had gone from acting opposite some of the best Shakespearean actors to starring in a national tour of “The Count of Monte Cristo.” The role brought him cash but also held him back. While O’Neill was still a boy, his mother became a morphine addict. One of his older brothers was a good-for-nothing sponger, and the other died as a child.

Each of these real-life events shows up in “Long Day’s Journey,” even down to the names of the brothers and parents, their professions and addictions. The play was never produced in O’Neill’s lifetime. Indeed, he presented it to his wife in 1941 on their 12th wedding anniversary, acknowledging in the dedication that it was an inappropriate gift but rightly calling it a play “of sorrow, written in tears and blood.” He asked that it not be produced until 25 years after his death, but his wife ignored his instructions and had it published in 1955, two years after his death in yet another hotel room. In 1962, Sidney Lumet made a film version with Ralph Richardson and Katharine Hepburn, but the play, which is filled with emotional exposition, has always been a beloved behemoth – for actors and audiences alike – onstage.

So it’s easy to see why people might not be drawn to “Long Day’s Journey.” Watching it is like watching tragic opera. It’s beautiful and elegant, but requires unflagging devotion and demands a level of attention that most audiences, unfortunately, find unachievable or at least uncomfortable. And just as with opera, if the performers are less than perfectly magnetic storytellers, the whole event can swirl into a nightmare. If you hear of a community theater doing this show, it’s likely to be something worth missing.

But think about going to Penobscot Theatre’s production. It’s not perfect. The performances are disjointed in such a way that the family spirit, cursed as it is, never really rises from the ensemble work of Ken Stack as James Tyrone, the once-grand actor and miserly patriarch, Nancy McDoniel as his drug-laced wife Mary, and Timothy Carter and Jimmy King as their whiskey-seeking sons. Yet there is still a sense of the greatness of the work, as well as the abyss of family secrets and pain.

Additionally, Merope Vachlioti has designed a gauze-walled set to represent the Tyrone’s decaying summer home in 1912, when the play takes place. Frank Champa’s period costumes reflect that same distant grandeur, formality and tatteredness, and lighting designer Lynne Chase adds a dappled, haunted quality.

The cast doesn’t run away with this show. Quite the opposite. The script gets the better of the cast – or at least that was true on opening night. Yet I found myself intrigued with this masterpiece, its circular structure – so much like that of an alcoholic’s dance with addiction, or a child’s inability to work through the past – and its underlying sympathy for the knots, rather than embroidery, that tie some families together. Mark Torres, who programmed the season, made a thoughtful and difficult choice. “Long Day’s Journey” is the boldest expression to date of his determination to bring great literature to the stage. It is a big chance for small theaters to take such a risk.

For this show, the audience has to be willing to take a risk, too, to take that descent into intense drama, near tragedy. It’s unlikely that a performance of “Long Day’s Journey” will come this way again for a while. So see it for the literature. See it for the wrenching family revelations, the theater, the American-ness of it all. Or for O’Neill, whose autobiographical art has largely stayed within the academy and therefore is seldom given voice for the rest of us. The Penobscot production is a reminder of just how tormented, poetic and astounding that voice is.

Penobscot Theatre Company will present “Long Day’s Journey into Night” through March 20 at the Bangor Opera House. For information, call 942-3333 or visit www.penobscottheatre.org.