Withered by cancer and riding in the back of a limousine en route to a David Letterman appearance, singer-songwriter Warren Zevon got a call from The New Yorker magazine. A reporter wanted an interview with the terminally ill singer. Zevon had just two words for him: "Too late." The subtext, of course: Where have you (and your magazine) been for the past 25 years?

Robert Earl Keen may wonder the same thing, but thankfully the media and music lovers are starting to catch on while Keen is still hale and hearty. The musician from Texas doesn't sound much like Zevon, but until recently has been similarly neglected by mainstream media and radio stations. The cult following he's developed after touring heavily during the past couple of decades is strong in the greater Bay Area. He performs Dec. 2 at the Mystic Theatre.

Like many accomplished musicians, Keen is impossible to categorize: his music combines elements of country, folk, rock, Tex-Mex and even has Celtic and gospel influences. His latest album, What I Really Mean, features the single "The Great Hank," a warped tribute to Hank Williams. In the song, Keen finds the legendary country musician playing a bar in Philly, dressed in drag, his mascara smudged by a tear. Good ol' boys may not get the irony, but Keen doesn't care—for 20 years he's followed his own muse and let his creativity lead him.

"I got a little bit heavier than I thought I was going to on this album," Keen recently told the Arizona Star. "The lyrics are more bent and colorful than I thought they would be. I went into this album thinking it would be more like a jam-band record. The words didn't have to mean a lot as long as they lifted you up and made you feel good. But it ended up being much more than that. I don't think you can always control your creative muse."

Even if you haven't heard much of Keen, you may have heard his songs, which have been recorded by Nanci Griffith and Gillian Welch, and by Keen's old pal Lyle Lovett. Keen and Lovett used to kick back on a porch in Texas and bounce around songwriting ideas. Though Keen hasn't achieved Lovett's level of fame, he has developed an intensely loyal following who pack his live shows.

It's the live performances where Keen really shines. Though he sees himself as a songwriter first, his shows are a rollicking good-time, a party of upraised glasses, high-stepping and exuberant howls. His October appearance at San Francisco's Hardly Strictly Bluegrass festival in Golden Gate Park had thousands of fans new and old dancing on their picnic blankets and tossing kids in the air.

After the party is over, what makes the music so memorable is the songwriting. Every Keen song is an engaging short story, ranging from the redemption of "I'm Comin' Home" to the deep longing of "The Raven and the Coyote." Some songs, such as "Feelin' Good Again," are exultant (a broke Keen finds "three 20s and a 10" in his pocket and can buy a round); others are whimsical, like "Merry Christmas from the Family." That's a story of a Texas Christmas replete with the cousin who can't stop talking about AA and the essential trip to the convenience store for "a can of bean dip and some Diet Rites."

In his press notes, Keen calls "What I Really Mean," the title cut from the new album, "a total road song." He says "The Wild Ones" is a determined man's quest to find his lost love. "I have plenty of experience in that realm, so that was an easy song to write. There's optimism there; that once I track this person down I'm gonna talk 'em in to coming back."

As for the fear that his well of songs will dry up, Keen is sanguine. "I have a lot of songwriting friends [who] talk about losing their juice or not being able to think up stuff," he says. "I've never been worried about it. I think I'm actually getting better. If you came and asked me if I could write five songs for you before 6pm today, I'd say, 'Yeah, I could.'"

Robert Earl Keen performs on Friday, Dec. 2, at the Mystic Theater. 23 Petaluma Blvd. N., Petaluma. 8pm. $23. 707.765.2121.

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