It was an all-star lineup Saturday night at the Underground Concert series in Maplewood: the guitar playing of Arlo Guthrie, the piano artistry of Billy Joel, the social conscience of Pete Seeger, the wit of Tom Lehrer and the canny observations -- not to mention the R-rated vocabulary -- of George Carlin.

No, they weren't all in the basement of Maplewood Memorial Library, but two hours in the company of singer-songwriter Eric Schwartz made you feel as if they were.

This incredibly versatile songsmith filled the room with hummable tunes, haunting melodies, riotous observations and more than a few off-color punch lines and lyrics, making for an amazingly diverse evening of music and humor. Whether crooning a gentle love ballad or slaying the audience with ditty after ditty about everything from philandering presidents to the denizens of Washington Square to the peculiar habits of pot smokers, Schwartz is a master craftsmen, able to hold his audience's keen Interest through a marriage of incisive humor and intelligent music.

This being a family publication, some of Schwartz's lyrics and song titles will not be spelled out here verbatim. And that's a pity, because while his language might offend the faint of heart, it never delves into the gratuitous realm of an Andrew Dice Clay. Think more a Carlin commentary set to a tune by, say, Peter, Paul and Mary. Early in the first set, after using a particular expletive, Schwartz quipped, "We're in a library -- this is a place of learning. There are no bad words here."

And the brilliance of Schwartz's music is that while you're laughing so hard that your face hurts, your brain is reeling at the sometimes-not-too-funny realities of life.

Schwartz's performance style is as flexible as his songwriting, lending the appropriate tone or quality to each piece, be it a country twang, a Cockeresque growl, a comically nasal drone or just a pure baritone sound.

Oh, and did I mention that you may as well check your political correctness at the door? Nothing is sacred here, and that's as it should be. When comedy -- or any art form, for that matter -- is "careful," it loses its vibrance and resonance. And Eric Schwartz is nothing if not vibrant and resonant.

Among the best songs of the night -- in terms of humor and its ability to provoke thought -- was the finale. Dealing with the karma awaiting the assailants of Abner Louima and Matthew Shepherd once behind bars, the title may be withheld here, but the concept is universal: you're gonna get yours in the end and we're gonna be there to laugh.

The comic vein was further explored in "charliesomething," in which Charlie Brown writes a letter to kid sister Sally filling her in on the exploits of the now-adult, dysfunctional "Peanuts" gang: Charlie Brown is gay, Linus is on the run after growing pot in the Pumpkin Patch, Snoopy's been neutered, Franklin shot Tupac Shakur, Pigpen has ODed -- all to the tune of the famous "Peanuts" theme.

Taking on a country twang, Schwartz wonderfully delivered an ode to his grandfather in "Moishe the Kid," who's got "shtetl dust in his blood" as he wreaks havoc on unsuspecting parking violators.

Most reminiscent of Lehrer was "The Psycho Ballet," which Schwartz said took "a year of research." detailing the surreal human mosaic~ inhabiting the Greenwich Village landmark of Washington Square.

Turning away from comically R-rated material momentarily, Schwartz displayed his impressive musicianship on some beautiful ballads. "Sunday Blue," to the tune of '`Say It Over (And Over Again)" by Frank Loesser and Jimmy McHugh, featured the evocative imagery of Schwartz's lyrics about "one Soho day in the rain." On "That's How It's Gonna Be." Schwartz's rocking piano playing called to mind Billy Joel in his "Piano Man" heyday. And he combined beautiful lyrics, impressive guitar fingering and harmonics filled with longing on "Only Be," inspired by his family homestead in Vermont.

Falling between the two ends of the spectrum were songs that combined the whimsy of his comedy and the tenderness of his ballads. What Kander and Ebb did for the menage a trois with "Two Ladies" in "Cabaret," Schwartz takes a few steps further in "Me 'n' Jenny and the Lovely Marilu." evoking an intriguing mix of humor and poignancy. In "Hattie and Mattie," Schwartz effectively blended sweetness and wit in telling the tale of two senior citizen lesbians -- complete with Alice B. Toklas brownies.

With no two songs truly alike - but each as entertaining and musically impressive as the next -- Schwartz's unique style of music blends everything under the sun into some of the most original and entertaining songs crammed into two short hours. With social commentary, tender ballads and scatological scatting. Eric Schwartz is a one-man band!

For information on the Underground Concert Series, see the "Concerts" listing in the Stepping Out calendar on Page B6, Tickets are available online at www.undergroundconcerts.com and in Maplewood at Sweets & Treats Bakery, the Robin Hutchins Gallery and the Tamaya del Sol Cafe.