'This American Life' reliably delivers true stories told truly

Telling a true story can be a tricky business, especially the truth part. After dragging the darn thing out of the river, you want to dry it out, sand it down, polish it. You want to structure the story for effect, usually with an accent on the rousing finale. If you're a reality TV producer, you also want -- no, need -- to tweak it, to cut a scene, perhaps, or create a new "real" one. Never underestimate the draw of a good catfight. Fur flies.

But "This American Life," Ira Glass's Public Radio International show, doesn't hammer narrative segments into neat shapes. It lets stories be stories. That's the reason I'm a fan of the weekly radiocast, which originated in Chicago in 1995, and that is why I have high expectations for Showtime's new TV adaptation, which premieres Thursday at 10:30 p.m. I'm hoping Showtime will present the pieces in all their jagged glory.

Yes, "This American Life" can be irritating, as the eccentricities become self-conscious and even self-parodic, or as Glass stammers a little too enthusiastically. But it nonetheless stands as a beacon of naturalistic, honest storytelling in a world so often misrepresented by "Dateline," or "The Real Housewives of Orange County," or, Lord save us, Nancy Grace. Glass and his staff try to mine only the naturally occurring dramas and comedies of ordinary lives, without wrapping them in plastic.

All fans of "This American Life" have their favorite segments. One that imprisoned me in my car was a 2002 piece about how a phone message in which a mother yells, "You and the little mermaid can go [expletive] yourselves," became a sensation for Columbia University's class of 1990. The piece, by Jonathan Goldstein, kept digging back into the family history behind the message, but it also evolved into a microcosmic study of how culture works. The "Little Mermaid" message was an early form of viral video, or a newfangled version of a chain letter, as it got forwarded exponentially via the campus phone system.

When I listen to the best of " This American Life," like the "Little Mermaid" segment, I feel as though the reporters -- and they have included David Sedaris, Sarah Vowell, and John Hodgman -- are discovering their stories along the way. It's as if he or she is following a maze of information who knows where. With all due respect to the gracious and yet artificial Diane Sawyer, they do not "pretend discover." And their surprise at the twisting and turning of the story feeds into the way they present it. Sometimes, a "This American Life" piece will indeed wind up in a familiar place, but you really didn't know it would from the start.

Another of my favorite pieces, about a man named Lenny and the true identity of his father, seemed to develop from peak to peak, to the surprise of Glass, the listeners, and Lenny himself. The 2005 segment was cinematic as it spanned decades -- Lenny learning that his late black-sheep uncle might be his genetic father, Lenny miraculously recovering his uncle's years-old DNA, Lenny finally receiving the results of the test. We even hear a tape of Lenny, alone, at the moment he opens the letter, when he learns the truth about himself.

As that tale unfolded, I felt a rare intimacy with Lenny. Partly, that intimacy is indigenous to radio, as the voices get inside your head and spark your own personalized visuals. While TV tends to hand you a finished product, radio expects you to take in the material and complete it yourself.

But the intimacy I have felt listening to "This American Life" also comes from the show's skillful, respectful approach to the material. Sometimes, the basics are enough.

Matthew Gilbert can be reached at gilbert@globe.com. For more on TV, visit boston.com/ae/tv/blog/.