Eugene O'Neill's masterwork is a long play, and it should be played as slowly and heartrendingly as a Mahler adagio. Such a tempo, with the emotional depth to sustain it, is followed by the Renaissance Theatre Company's deeply felt production, which runs about three and half hours. Yet, for its length, Long Day's Journey is a marvelously compact play. With sorrow softened by love, pity purged by forgiveness, despair diminished by acceptance, O'Neill condensed the emotional history of his family (renamed "Tyrone") into 16 waking hours of an August 1912 day, and then further distilled those hours into their quintessence. And as one's own long day wanes, the drama hits home with ever greater weight and truth.

Directed by David Ellenstein with a fine feel for physical and emotional spaces, this handsome production boasts an evocative and well-carpentered set design by Marty Burnett, delicately lighted by Karin Filijan, easygoing period costumes by Jeanne Reith Waterman, and a cast capable of intimate ensemble work and some striking individual moments.

Kathy Kash enlarges a small servant role with some lively Irish attitude. Brendan Ford finely balances the tormented temperamental contradictions in the melancholic, madcap, misanthropic character of ne'er-do-well son Jamie Tyrone, and as his younger brother Edmund (the playwright's stand-in for himself), Sean Robert Cox captures the sense of a fledgling genius who, while struggling through the bogs of his own troubles, seems nonetheless to be observing his family through the ironic eyes of the future dramatist. The poignancy of their scenes together, caught by Ford and Cox, lies in how the brothers are always nearing the verge of a fuller emotional connection, with each other and their parents, that is never quite achieved.

Jonathan McMurtry brings the many veteran shifts and dodges of his huge stage experience to the part of the father, retired matinee idol James Tyrone—sometimes trying on the exaggerated diction and Shakespearean airs and graces of a 19th century tragedian, but most emotionally authentic when the character recounts the tale of his career sellout for success in cheap melodrama. And, in the role that is the play's tragic focus, that of the morphine-addicted mother, Mary Tyrone, Rosina Reynolds wisely makes her character less a vague and meandering "mad ghost," despite her pale wraithlike mien. Insteead, Reynolds actually grows clearer and more precise as Mary descends into her drugged reveries, becoming pathetically detached and separated from the present world of her family; it is a lucid madness. And in the pathos of the play's final midnight tableau—with the mother deep in drugs, the males all having much drink taken—there is almost a redeeming sad sweetness as Mary Tyrone's wandering words return at last to soft memories of her husband and their first happiness together.

"Long Day's Journey Into Night," presented by Renaissance Theatre Company at the Lyceum Space Theatre in Horton Plaza, San Diego. Tues., Wed.-Thurs., Sun. 7 p.m., Fri. 7:30 p.m., Sat. 2 & 7:30 p.m., (Sun. June 10, 2 p.m.). May 11-June 10. $20-35. (619) 544-1000.