For an upbeat guy, Alan Jackson sure sings a lot of sad songs.

About half the 12 tracks on his new Arista/Nashville album What I Do, released Sept. 7, deal with lost love or loneliness.

"It just happened that way," said Jackson, who speaks in the same lazy drawl that he sings in. "It wasn't anything planned. Even some of the lighter songs are about that same subject. But that's always been my favorite kind of song anyway."

What I Do is Jackson's 14th album and follows the triple platinum Greatest Hits Volume II collection.

Long after most of his contemporaries have faded, he remains one of Nashville's biggest stars. He snagged a leading seven award nominations in August from the Country Music Association, including one for entertainer of the year. Jackson is scheduled to perform tonight at West Palm Beach's Sound Advice Amphitheatre.

"Alan has a gift for capturing life in a song; he's done it time and again," said Gwen Foster, music director at radio station KNIX in Phoenix. "He's not a fancy guy. He's not a dynamic or explosive entertainer by any means. The way he expresses himself through the songs is what grabs people."

The new album, on which Jackson wrote five of the 12 tracks, is often melancholy, and already has reached No. 1 on Billboard's Top 200 and country charts. He sings about a failing relationship in You Don't Have to Paint Me a Picture, learning to love again in There You Go, and the pain of losing a loved one in Strong Enough.

They're not all sad. The first single, Too Much of a Good Thing, is about a couple so happily in love that he sings, "I should be scared, it's so right." The song already has cracked Billboard's country Top 5.

"It's a bit of a shadow of what my life is really like," said Jackson, who's been married to his wife, Denise, for almost 25 years.

The Talkin' Song Repair Blues is a hoot, with Jackson, who loves to tinker with car and boat engines, singing about a songwriter who turns the tables on his auto repairman.

After ticking off a litany of problems with the car, the mechanic says he's a songwriter too and plays a tune "by the grease rack."

"Well, I gave him my most sorrowful look / And I said, `This song's got a broken hook / I can order you a new one from Nashville but it won't be cheap / And I know you've been using a cut-rate thesaurus / 'Cause your adverbs have backed up into your chorus / Now your verse is runnin' on verbs that are way too weak.'"

Jackson is heartbroken, but still funny on If French Fries Were Fat Free, singing in the chorus, "If french fries were fat free and you still loved me / What a wonderful world this would be."

"I originally had it `If Krispy Kremes were fat free' but changed it to french fries because I thought it was more universal," he says. "My wife makes fun of me because I have a lot of songs with food. But I say write what you know, and I know about food, cars and broken hearts."

The album ends with the poignant To Do What I Do, an inspiration for struggling musicians and one of Jackson's favorites.

"Most singers who come to town go through that -- playing in empty rooms and for people who don't pay any attention," he said. "You don't take it to heart, but that's the way it is, and then all of a sudden you're a big star and people don't realize or they forget what you really went through to get there."

Jackson, 45, went through quite a bit.

He grew up outside Atlanta in Newnan, Ga., and began playing in bars in his 20s. He specialized in singing traditional country songs by heroes Merle Haggard and George Jones, along with the hits of the day.

After moving to Nashville in 1985, he worked at the cable network TNN while developing his songwriting. His wife worked as a flight attendant to pay the bills and helped get his career going when she noticed country singer Glen Campbell at an airport and slipped him a demo tape. Their chance meeting led to Jackson writing songs for Campbell's music publishing company.

Arista signed him in 1989, and along with Garth Brooks and Clint Black he was part of a wave of new stars that reinvigorated country music.

He's remained a staunch traditionalist throughout his career -- and his fans seem to love him for it. He's had 31 No. 1 singles, sold more than 40 million albums and won 16 Country Music Association awards.

He has a knack for hitting the right tone. In 1994 he sang Gone Country about carpetbaggers descending on Nashville when the format jumped in popularity. In 1998 he had Little Man, about the economy squeezing out small businessmen. In 2002 his Where Were You (When the World Stopped Turning) expressed the shock of the Sept. 11 terrorist attacks as well as any song did.

Earlier this year, with the country in the midst of war, he had another big hit with the sentimental Remember When, a ballad about an older couple reflecting on their lives.

"When it's all said and done, I think Alan will be remembered as one of the better songwriters in country music," said country newcomer Dierks Bentley.

"He's also one of the few artists out there who serve as a bridge," Bentley added. "He loves Hank Williams and Lefty Frizzell and Vern Gosdin and all of these guys, but many of his fans are in high school and don't know who Vern Gosdin is, or Johnny Cash or Hank Williams or George Jones. So Alan is an important bridge to those earlier artists."

Jackson figures he'll just keep doing what he's doing and the rest will take care of itself.

"What I Do is the perfect title for this new album because that's just it. This is exactly the kind of music I wanted to make when I was starting out," he said. "Had it not worked out for me, I guess I'd still be doing it -- except in some bar and nobody would know it."