As the creative whirlwind subsided, Brooks had to hurry up and wait. ''It took me more than a year to find a distributor,'' he says. ''Every studio turned it down. Some turned it down twice. Every record company turned down the song as well.''
Then in 1977, things began to light up. Columbia agreed to distribute the film (which would become a solid hit). Suddenly, it was time to record a single, and Brooks tapped 20-year-old Debby Boone. Her main claim to fame: She was one of 1950s teen sensation Pat Boone's four daughters, who sang in a gospel quartet.
Boone recalls the gig as something of a fluke, the result of a ''falling-out'' between Cisyk and Brooks: ''I think there was some kind of love interest between her and Joe.'' (Citing Cisyk's death from cancer in 1998, Brooks declined to comment.) At any rate, the recording process was no picnic for Boone: ''I had no freedom whatsoever. Joe told me exactly how to sing it and imitate every inflection from the original recording.''
Still, the record was a monster hit, and reporters wanted to know who, exactly, was lighting up Boone's life. Her surprise answer -- God -- wasn't calculated: ''I remember someone asking me if I was singing it about my dad. And then you're like, well, if you want to know the truth, this is my interpretation of the song.'' No one was more surprised than Brooks. ''He didn't like that at all,'' says Boone. Brooks is more diplomatic: ''Debby put a religious spin on the song. That was certainly not the intention when I wrote it. But I can see why it could be interpreted that way by many people.'' The two parted ways after the recording's success, reuniting only once, for a performance of -- yup -- ''You Light Up My Life'' on NBC's Night of 100 Stars III in 1990. ''He played the song and I sang it,'' remembers Boone. ''He was really very nice. But that was years after the fact.''
By the time Oscar night rolled around, Brooks was the heavy favorite, Boone had a fever, and a choir incorrectly billed as ''children affiliated with the John Tracy Clinic for the Deaf'' were assembled to sign the song. The spectacle of a radiant, angelic Boone, backed by children rendering the lyrics in sign language, tugged at the heartstrings of the audience. What none of them knew was the choir was actually composed of elementary-school students from Torrance, Calif., who were not deaf at all.
''I never heard that!'' Boone exclaims. ''The whole thing was bogus? I never heard that! But again, I was so out of it, if there had been a way of hearing about it that night, I wouldn't have heard it.'' Boone calls her fever that night a blessing in disguise, insisting ''I was so out of it, I couldn't sabotage myself. It was really just put one foot in front of the other: Sing the song and get me home to bed. How else could I open my mouth and sing a note on the same stage as Aretha Franklin [who performed ''Nobody Does It Better'']?''
Oscar in hand, Brooks went on to direct a few more films, then left mainstream showbiz to pursue writing and composing a musical version of Fritz Lang's Metropolis (now touring in regional theaters). Boone ''slapped together'' a solo album and a concert tour, and though she would never again reach the same ''You Light Up My Life'' heights, she was back at the Oscars the following year, performing the nominated ''When You're Loved'' from -- anyone remember? -- The Magic of Lassie.