Los Angeles, everybody knows, is the place to spot celebrities. But at S.I.R. Studios, a deceptively inconspicuous major Hollywood recording facility that looks like a rundown auto parts warehouse, a door opens and out steps a man you'd swear was a celebrity ghost. We all know his quizzical face. It peered at us, eager and a little bit puzzled, from record covers in the '70s, when he sold untold millions of albums as lead singer of the Commodores, and in the '80s, when he sold untold millions more as a solo balladeer with easy hits like ''Say You, Say Me.'' But until this year, Lionel Richie hadn't released an album since my God, was it 1986? As the restless pop-music world measures time, that could just as well have been before Noah's flood. He hadn't meant to disappear; in 1987, when he finished his last major tour, he just figured he'd take a peaceful year off. Then in June 1988 his wife, Brenda, found him in a clinch with another woman at 2 a.m. on a Beverly Hills street and got arrested after starting a screaming brawl. The police said they found her in the other woman's apartment, with blood on the floor and walls (the police have never said whose it was). With his personal life falling apart, Richie stretched his year off into two and kept stretching more; after he'd been away five years, you had to wonder whether he'd fallen clean off the earth. Richie hadn't, of course, and this year, at age 43, he finally began a careful comeback, releasing a greatest-hits album that (just as a swimmer might dip a cautious toe in uncertain water before plunging in) also offers three new songs. At first he wouldn't talk to the press. But when one of those new songs-a fluid little number called ''Do It to Me''-became a respectable pop success and an outright R&B smash, Richie suddenly had success to talk about. So that's no ghost haunting S.I.R. Studios. ''I felt so exposed,'' he says of the recent past, ''because this is a Southern guy you're talking to, not a city guy. And when I say exposed, I wanted to go back and close the door and get myself together. My insides were visibly on my outside, and I had to do something I'd never done before. I had to deal with it.''

So what happened for five years? The key question, it turns out, is what happened for the years before that, when he lived in what he now calls a ''fairy tale,'' all the years since 1968 when ''I walked into college,'' he says, ''and met these guys called the Commodores.'' We've retreated to a subdued, almost darkened back room at S.I.R., where Richie sits erect and alert on a stool, seeming half like the confident power figure he used to be- he leans forward often, taking his visitor into his confidence with a quick tap on the knee-and half like an obedient schoolkid, politely waiting for someone to ask him something before he'll presume to speak. So five years ago some emotional bills began coming due? He readily agrees, his voice all at once hushed: ''It's called years of saying I'll get to that later, put that off for now, you know the Grammys are coming up Thursday, I don't want to deal with that now.''