I am not neutral when it comes to Al Green, not since I wept in the parking lot of his Memphis church during a service two years ago, wandering among the small herd of vans, Chevys, and faded Gremlins, overcome by the ecstasy he had conjured in his working-class flock.

Inside, the Full Gospel Tabernacle Church churned deep into its third hour. The congregation was on its feet, clapping and dancing as the choir unleashed all the joy in its lungs. People were speaking in tongues and rattled by tremors, soothed only by the church elders who walked up to them and carefully wrapped them in white sheets.

When I made my temporary exodus, a heavy-set man in a shiny suit, standing in the foyer chatting with friends, pushed the door open for me and smiled, as if he had seen this kind of tear-stained exit thousands of times. What I did is perhaps what many of the tourists--Japanese, German, or the kids up from the University of Mississippi for the day--have done when Al Green had whipped them into such high emotion. They topped off and then just went outside and cried against a Buick.

The average person just cannot go head to head with Green when he is cranking up the ecstasy meter. He glows with a weird, infectious happiness. This joy, he would insist, is just the Holy Spirit playing him like an organ.

But at one service, I remember him smiling and singing in my direction, and I started to wonder if maybe this is what mania looks like. Green's new autobiography, "Take Me to the River," opens with a somewhat disturbing third-person description of the three Al Greens warring within him. Another jarring tell appears in the brilliant Robert Mugge documentary, "The Gospel According to Al Green." Green--handsome, charming, supremely talented--relates the infamous story when an unhinged lover dumped a pot of scalding grits on his back and then fatally shot herself in his bedroom. Green's face goes slack. "The thing I want to ask you today is," he says to the interviewer, "Did that actually happen? And I'm not joking. I'm asking you a question." This is what happens when life gets too dark for Al Green. He tops off and loses his sense of reality.

The brilliance of Al Green is that he has harnessed whatever storm brews within him to indisputably good ends. Most Sundays, he arrives at Full Gospel Tabernacle about an hour into the service, dressed in a brown robe. After the choir warms him up, he walks to the lectern and begins to preach against the band's vamp. "That reminds me of something," he'll say, as he ends a line of biblical quotation. "And that something is Jeeee-sus..." His voice lifts off into a few pure, falsetto notes. Then eyes closed, he pats the air. "No, bring it down," he says firmly, and the dirty-organ player eases up, and the drummer switches to brushes. "I need it sweet," Green nearly whispers, then he launches into a gospel hymn, one he likely learned as a boy, singing in the family group, the Greene Brothers.

In this version, the song runs some 20 minutes long. He rolls through trills and barks and full-throated bell tones until he is staggering around the pulpit. Then, as he grips his forehead and whips his torso toward the ground, he starts to climb back up, in the music, in his muscle, until he has worked his way back seamlessly to preaching biblical verse again.

This is Green's gig almost every Sunday. On Wednesdays, he leads the Bible study. If the setting were more glamorous, Green's decision, two decades ago, to walk away from his pop career might answer better to the cynic's grumbling that, since no one can last very long at the top of the charts, Green had simply found a way to make a graceful exit.

But the Full Gospel Tabernacle Church is no substitute for the glitter of Vegas. It doesn't compare, for that matter, with the megachurches of Dallas or Denver. Green preaches to a small group of regulars in a modest building decorated with a couple of folk murals. He lingers appreciatively over a recital of the items in the cafeteria's box lunches available after the service. Each person approaching the offertory plate gets a personal greeting ("And how are you doing there..." "I like those shorts..."), often by name, as the band keeps up its riffing. In Memphis, it is Al Greene who makes his parishioners feel glamorous.

"I think they are people that lost it along the way, and come back and join up again. A lot of people like that go to our church," says Green on his cell phone from his car. He is in Atlanta for a book signing. Green speaks the way he sings, slowly and seriously, then giving way to lilting asides, jokes, inner dialogues issued without preface. "A lot of people, oh man, who had a lot of problems. 'But I'm going to try it again.' So always the persons keep reaching up there, thinking, 'I'll just give it one more...'"

Green doesn't lose heart when they drift away again. "I know what they're dealing with. I know what they're up against," he says. "But I still go back to the first principle: If it is in them--the Full Gospel Tabernacle--if it's in them, they'll come back to it. They'll come back. You can't stay out there and have known Him. You have got to come back.

" He lets out a whoop of ecstasy. He says something to his manager, Lisa, riding with him in the car, and I gather she is cautioning him not to get too excited and scare the journalist.