LIZ PHAIR may well be a major reason the hugely successful Lilith Fair tour exists. Though Sarah McLachlan had the business savvy, the focused dream and her pick of stellar female performers, her ideas may never have been heard if Phair hadn't helped open the floodgates for female songwriters when she burst out of Chicago in 1993 with her wildly hyped debut, Exile in Guyville. What the debut lacked in record sales, which were moderate but impressive by industry standards, it made up for in critical acclaim, for both her bold songs and inventive guitar playing.

As she was thrust up into the media whirlwind with her femme fatale pose visible on many a magazine cover, it opened the doors for other blunt and guileless female songwriters, such as Alanis Morisette, as well as the more subdued but motivated earthgirls of Lilith Fair to be heard by a male-dominated industry.

Exile, a tribute to the Rolling Stones' classic Exile on Main Street, was a timepiece of a naive, twenty-something girl with some serious man troubles and a desperate need to fit her square self into the circile of the tightly knit Chicago indie-rock scene. It comprised self-conscious stories laden with foul-mouthed sexual fantasies that, surprisingly, appealed to men and women equally. Its follow-up, Whip-Smart, an artistic flop by no means, suffered disappointing sales and left her feeling more whipped than wise.

But what happens when a female over-scrutinized, overnight success story disappears for four years to do career-threatening things like get married and have a baby? If you're Liz Phair, whose latest offering is whitechocolatespaceegg (Matador), not only do you get your petite girlish figure right back and just glow in your press pictures, you also come back much more stronger and wiser. And, more importantly for your career, music critics were waiting for your return, and they also think you've become a more mature, well-rounded songwriter. The luch of some people.

Phair's personal growth and lengthy break from the biz have transported her beyond the longing girl of Exile in Guyville.

"I feel totally different from that person. I don't feel any of that gangly awkwardness, or need to please or present myself in a certain way," she says.

And to Phair, now 32 and a doting mother to 1-1/2-year-old Nicholas, her songs are also still her babies, and performing them more successfully than she has in the past is an important new goal. Phair road-tested her songs on the summer Lilith Fair tour, and this fall, she's embarked on her first full-band tourn in more than five years, which brings her to a sold-out show at the 9:30 Club Monday.

"I thought I came at a visible time and had an impact [on women in music] and I felt like that's what I contributed to Lilith Fair, but I learned som much from those women. About vocal expression, and the way they perform so boldly and are so in control of an audience that large. I feel so helped along by what they're doing, and it allowed me to come back and do it again," says Phair.

Phair, who has suffered from debilitating stage fright in the past, now states, "I'm kind of ready to just rock out and not be afraid. The songs feel rich and deep to me, and I feel I wnet somewhere with my songwriting. The titillating aspects of my earlier work were great for magazines and for people to have arguments about in bars, but I didn't flourish under that. And the moments onstage are awesome now; I don't know what's gonna happen, but I have much more control now. I'm an excitement junkie, and playing feeds that."

And making whitechocolatespaceeg fed her addiction to excitement as well.

"There was no agenda with this one. It was like making Exile all over again."

Phair, who shares production credits with the coolly primitive producer of her last two records, Brad Wood, and the more slick hit-maker Scott Litt, says, "Brad and I had the most fun making this one. We experimented a lot. It was like, hey, let's try this mike now, why don't we swing it over our heads?"

"The new songs that came out really surprised me. I found they can really take you beyond the ordinary day to day."

Perhaps she's referring to songs such as "Big Tall Man", in which she takes on her male alter ego, or the abusive big brother in "Only Son", whose sad but barely repentant viewpoint she sings from.

But it's not as if Phair can't still titillate with songs about bad Johnnys of her past. The "Johnny Sunshine" of Exile in Guyville who left her with nothing has turned into "Johnny Feelgood", the first single expected from whitechocolatespaceegg, who makes her feel strangely good about herself until "he knocked me down, started dragging me around, in the back of his convertible car".

And Phair still simmers with rock-star rebellion rooted in her upbringing in Chicago's upper-class suburbs.

"The older you get and the more you take on, the more you can rebel against your husband, men in general, the sisterhood, your mother, your neighbors... It seems like I just can't get my house clean enough sometimes. I still have all the fantasies and the questions."

"And my mom is still always good for rebelling against," Phair jokes.

Even so, in a song about a real conversation with her mother, "What Makes You Happy", she feels more of a need to have Mom's blessings. Phair tells her about the man she met in a restaurant (no, not another bar, Mom); okay, he may have an ex-wife but "I swear this one is gonna last, all those other bastards were only practice".

Though Phair's very happy with her husband, film editor Jim Staskaukas, it seems she could've written the theme song to the biting sitcome Married... With Children the way she ruminates on the realities of it all, as in "Go On Ahead". It's unfeigned and chilling when she sings, "You say you're a ghost in this house and I realize I do think I see through you / It's the death in our love that has brought us here / It's a birth that has changed our lives." And in whirlingly catchy "Love Is Nothing", she sings, "You gotta pick up the little pieces every day."

"I want so badly to know what goes on in other women's lives, their daily struggles, and to get below the external manifestations of living our lives," she explains. "The people in the Midwest don't tell you the real stuff. I need someone to write the handbook. Where's the guidebook? I feel like someone's gonna blow out of control any minute. Why can't I enjoy doing all these things being a wife, having a child, a career and cleaning the house?"

LIZ PHAIR -- Appearing Monday at the 9:30 Club.