After watching the final dress rehearsal of his show on Jan. 24, the composer and lyricist of "Rent," Jonathan Larson, 35, returned to his Greenwich Village apartment. His body was found several hours later, collapsed on the kitchen floor. The cause of death, according to the coroner's report, was an aortic aneurysm.

The young songwriter's life had been entwined for seven years with his semi-autobiographical musical, which re-creates Puccini's 1830s Left Bank bohemians as struggling East Village artists in 1990s Manhattan.

The future of "Rent" will hinge on its reception on Tuesday, when it opens, appropriately enough, in the East Village -- at New York Theater Workshop -- directed by Michael Greif (the artistic director of La Jolla Playhouse).

With a cast of 15 young performers, a 35-song score, a five-piece band and a budget of $200,000, it is the biggest undertaking in the workshop's 16-year history, according to its artistic director, James C. Nicola.

"We had this piece in mind when we raised the roof of the theater last summer to contain it," Nicola said. To some, including Larson's mentor, Stephen Sondheim, "Rent" might have been the composer's breakthrough work.

Sondheim said that Larson had been one of the few people today trying "to blend contemporary pop music with theater music, which doesn't work very well; he was on his way to finding a real synthesis."

"A good deal of pop music has interesting lyrics," Sondheim said in an interview. "But they are not theater lyrics." A songwriter who works in the theater, he emphasized, "must have a sense of what is theatrical, of how you use music to tell a story, as opposed to writing a song. Jonathan understood that instinctively."

After that final dress rehearsal, Larson gave an interview to The New York Times at the workshop and spoke of "La Boheme," which he first saw when his parents took him to a puppet version for children.

As he grew older, he said, he realized that Puccini's bohemians were not just four wisecracking guys who wear one another's clothes, eat one another's food and spend one another's money when they have any.

He recognized himself and his East Village artist friends in the story: struggling young people who hold down numbing jobs to support their artistic dreams, while coping with drugs, poverty, sexual confusion and AIDS.

There would be brash humor, buzz-saw rock and exuberance in Larson's East Village bohemia. But he also wanted to tell the truth: "la vie boheme" is a fallacy; the artist's life on Avenue A is precarious.

He had only recently learned that the opening of "Rent" coincided with the 100th anniversary on Feb. 1 of the first performance of "La Boheme" in Turin, Italy, led by a young opera conductor named Arturo Toscanini. "It's the weirdest thing," he said in the Times interview. "People try all the time to do stuff like this on purpose, but this is an amazing coincidence."

The lanky Larson, who had a mop top like Kramer's on "Seinfeld" was worried about the technical aspects of the show, especially the balance between the band and the singers ("It's the bane of my existence; I'm only as good as my soundboard operator").

But overall, he had been buoyed by the invited audience's enthusiastic response that night and was cautiously optimistic.

To support himself, he had worked for 10 years as a waiter at the Moondance Diner in SoHo. When "Rent" went into production last fall, he was finally able to quit that job. "I'm happy to say that other commissions are coming up, and I think I may have a life as a composer," he said.

But though the conversation touched on his childhood in Westchester, his years at Adelphi University, where he studied acting and began writing songs for the college cabaret, his music for film and children's television (including songs for "Sesame Street"), and his gratitude for Sondheim's support, Larson kept coming back to the characters he had created for "Rent" and how they were related to Puccini's bohemians.

"I analyzed the libretto, broke it down beat by beat," he said. "Who would these characters be in my world? That's what I kept asking." He dug deeper, going back to the autobiographical short stories of the struggling French writer Henri Murger from which the libretto of "La Boheme" is fashioned.

"Murger's characters are much grittier," he said. "It was really interesting. The more involved I got, the less I cared about  being true to Puccini."

In Larson's work, Puccini's Rodolfo, the poet, becomes Roger, the wiry punk rocker with dyed-blond hair who sings "Glory." He is a recovering heroin addict whose girlfriend killed herself after discovering she had AIDS.

Marcello, the boisterous painter in the opera, becomes Mark Cohen, a brainy video artist who escapes into his work. Mark's former girlfriend (the free-spirited Musetta in "La Boheme") is Maureen, a performance artist who has left Mark for a new lover, Joanne.

Puccini's Colline becomes Tom Collins, a gregarious gay black man. One night, after he is mugged, he is tended to on the street by a stranger:  Angel Dumott Schunard, a cross- dressing Hispanic man who, like Collins, is HIV-infected. They fall in love, and the roster of bohemians is almost complete.

A power outage in Roger's building brings a volatile, vulnerable tenant named Mimi (after the tubercular heroine of "La Boheme") to his door with a candle she needs lighted -- as in the opera.

Mimi is a dancer at an S&M disco and an active drug user who is dying of AIDS. She soon demolishes Roger's resistance and together they sing a grunge love duet.

Many of Larson's ballads and hard-driving rock songs mirror specific arias and ensembles in the opera. Puccini's winter crowd scene outside the Cafe Momus becomes a Christmas Eve chorus at St. Mark's Place, with street vendors selling "hats, bats, shoes, booze, mountain bikes, potpourri, leather bags, girlie mags, .45s, AZT."

Even Puccini's Act 4 comic scene, when the men, singing falsetto, do a mock dance with one another, has been evoked by Larson: Collins, in his leather coat, and Angel, in a Santa's helper dress, disco dance on a table as Mark and Roger whoop encouragement.

Despite having directed an earlier version of "Rent" in 1994, Greif said he did not know Puccini's opera well.

"Jonathan is very excited by the parallels between the opera and the musical," he said the night of that final dress rehearsal. "I'm interested in the accessibility and vitality of the piece, completely apart from the opera. So we provide a balance. For people who know the opera, all the better. I'm sort of the watchdog for the unexposed."

Sondheim followed the progress of "Rent" from the beginning. An earlier incarnation was "really good, and really a mess," he said. "But I liked that he wouldn't give up, and kept trying to fix it instead of abandoning it. I thought Jonathan had started to solve the problem of focus, which is the hardest thing to do in the theater: telling the audience which characters to follow, cutting out the extraneous material. He was learning the only way you can in the theater -- by doing it. It can't be taught academically."

As head of the panel for the Richard Rodgers Studio Production Award, Sondheim helped "Rent" receive a grant last year.

The last time he spoke with Larson was a few months ago: "He called up with a problem -- not an artistic problem, a production problem. I gave him my usual 5 cents worth of advice: Theater is collaboration, you have to give ground to gain ground. If you don't want to collaborate, then be Wagner and get a King of Bavaria to support you so you can do it yourself."

Larson's debt to his mentor can be found in his verbally dextrous lyrics, in one instance, quite literally, when the battered bunch of dropouts and dreamers sings a wry toast to:

Emotion, devotion, to causing a commotion,
Creation, vacation, mucho masturbation,
Compassion, to fashion, to passion when it's new,
To Sontag, to Sondheim, to anything taboo.

On the last night of his life, Larson talked of something he had learned from a friend with AIDS: "It's not how many years you live, but how you fulfill the time you spend here. That's sort of the point of the show."