When they start a business school for pop stars, country singer George Strait will be a case study in the art of getting rich slow. There are rivals with fuller voices (Randy Travis), flashier stage shows (Garth Brooks) and hunkier looks (Toby Keith). But it's Strait who recently set a country music record by scoring his 50th No. 1 hit, edging ahead of the legendary Conway Twitty. And it's Strait who played to a thrilled-to-bits, near-capacity house at MCI Center on Thursday night.

So, here's the key question for a class in Strait 101: What's this guy got?

At this perfectly good, intentionally unspectacular concert, answers didn't immediately lunge to mind. You could quickly grasp why he'd be big, but it takes more time to figure out why he's immense.

Strait has the conventionally handsome looks of a guy on TV playing a senator, and when he sings he stands still, keeps a leather-booted foot tilted to one side, and occasionally strums an acoustic guitar. He smiles a lot, utters a few workaday blandishments and things like "Good evening, Washington!"

With a nine-piece band and couple of backup singers, he paced this concert so evenly it actually looked like clockwork. A square stage was set in the middle of MCI, with microphones on all four sides. He'd sing two songs, amble 90 degrees to the microphone to his left, sing two more songs, amble to the microphone to his left, sing two more, amble again and sing again.

Tick, tick, tick, until 25 songs and two encores later, he low-fived some lucky fans and strode out of the house.

Strait, who was born in the South Texas town of Pearsall, was among the first artists in the '80s to revive traditional country music, like Western swing and honky-tonk. There's nothing raw about his music, but you wouldn't confuse it with pop either, and he switches from smitten swain to heartbroken fool in a flash without pretending to truly inhabit either role. He lets the songs (which he doesn't write) do most of the heavy lifting, and nearly all are up to the task. On "Write This Down" he hands a love message to a girlfriend who is walking out on him. ("Take my words and read them every day / Keep them close, don't let them fade away.")

Women were ditching men in songs throughout this show, including the fed-up wife of a rodeo star of "I Can Still Make Cheyenne," who tells her husband she'll be gone by the time he's home. On "She'll Leave You With a Smile" Strait offered a warning to a friend who hadn't asked a certain lovely out on a date: "One day you'll pass her on the street/ With that guy you used to be."

Strait celebrated his good fortune in a cover of Merle Haggard's "My Life's Been Grand," and shifted to hoedown speed for a version of Bob Wills's "Take Me Back to Tulsa." He and the Ace in the Hole Band, as they're known, did an upbeat shuffle for the classic "Milk Cow Blues." One of his encores was Johnny Cash's "Folsom Prison Blues," a tune about a remorseful killer that Strait just seems too nice to pull off.

Despite the variety of sounds -- pedal steel guitars, fiddles -- what was striking about this career-spanning show was how little Strait's style has changed over the years. Which perhaps hints at the secret to his longevity. He never fell for any fads, like pop country, which has been the rage for years in Nashville. And curiously, almost never does interviews, in part because he doesn't like to.

This ensures that Strait is underexposed. He never overwhelms you, which makes him hard to dislike and inoculates him from the sort of backlash that waylaid Garth Brooks. In the parlance of politics, he has low negatives, not to mention something else that's very rare these days: mystique. It's hard to think of anyone else in the celebrity world who's been so popular for so long and who husbands access with such care.

"True to his Texas roots," read a sign on the video screen above the stage as the lights dimmed before the encores. Steady, charismatic, and just famous enough -- it's a smart way to stay in it for the long haul. When Strait sang "When Did You Stop Loving Me," one fan had an answer. "We've never stopped loving you!" she screamed.

Strait, at the MCI Center Thursday, is enormously successful -- partly because of what he doesn't do.George Strait's performance at MCI Center on Thursday night exemplified his long career: unspectacular, no-frills -- and, for the crowd, captivating.