LENOX >> On Saturday evening at exactly 6, the red "on-the-air" sign will be lit for one last time on the traveling set of the "Prairie Home Companion" live broadcast at Tanglewood.
It will be the 17th and final annual show hosted by Garrison Keillor and his troupe of actors, musicians and sound-effects guru Fred Newman at the Boston Symphony's summer home.
At 73, Keillor is a week away from retiring from the folksy, quirky, homespun soundscape of Midwest Americana he created 42 years ago, originally for Minnesota Public Radio. He has broadcast precisely 1,550 episodes since then.
In 1980, the show went national and is still heard by faithful fans on 690 public radio stations with an estimated weekly audience of 3.2 million.
Keillor acknowledges a special affinity for Tanglewood, a favorite stop during his frequent road trips. So it's fitting that his farewell live broadcast of "Prairie Home" will originate here. (His actual finale, to be broadcast next Saturday evening at 6, will be pre-recorded at the Hollywood Bowl the night before to spare the audience from roasting in the mid-afternoon heat, Pacific time.)
"There is no place like Tanglewood," Keillor has told The Eagle, citing "the ghosts of Hawthorne and Leonard Bernstein, the enormous Shed and the lawn beyond, and the loyal listeners who come."
"Every year they strive to prolong the encore beyond the all-time record, which I believe is 75 minutes," Keillor said. "We stand out on stage and sing and they sing with us and the cows come home and nobody leaves. This happens nowhere else in America."
A live video stream of this Saturday evening's broadcast can be seen via prairiehome.org.
The host, who has never used his name on the air, was traveling earlier this week and not available for an interview prior to his arrival in Lenox late Thursday, at which time he sequestered himself for script writing and a Friday evening rehearsal.
According to the show's marketing director David O'Neill, the Saturday broadcast will include all the regular features — sketches like "Guy Noir, Private Eye" and "The Lives of the Cowboys" performed by Keillor and his Royal Academy of Radio Actors; musical guests (this week, The DiGiallonardo Sisters, Heather Masse and Rob Fisher), "The News from Lake Wobegon" monologue, an audience favorite, and the faux commercials for Powdermilk Biscuits and the Ketchup Advisory Board.
Any surprises? Not to be revealed yet.
It all springs from the fertile imagination of a performer known to be painfully shy off-stage, but who comes across as garrulous and extroverted when he meets his listeners after the broadcasts.
A prolific essayist, columnist, novelist, storyteller, singer and sole scriptwriter for his show, Keillor explains that a writer never really retires.
But, as he told the Minneapolis Star-Tribune recently, "You come to the realization that you want to get some part of a normal life back."
His daily, five-minute "The Writer's Almanac" will continue to be broadcast nationwide, including on WAMC Northeast Public Radio at 8:45 and 10:25 a.m.
Keillor's new weekly Washington Post column, ranging from the personal to the political, is distributed nationally and appears on The Eagle's op-ed page.
He has a memoir and a Lake Wobegon screenplay in progress, hosts occasional cruises and will continue performing as a solo act around the country, at least a dozen times a year.
He also remains the proprietor of Common Good Books, the store he opened in St. Paul, Minn., 10 years ago.
He resides in the city with his wife, Jenny Lind Nilsson, a violist for the Minnesota Opera, and his daughter Maia, 18. His son from a previous marriage, Jason, works on the radio show. The family also has the apartment on Manhattan's Central Park West owned by Keillor since 1988.
The show will continue in repeats through the summer and early fall, when mandolin maestro Chris Thile, 35, groomed by Keillor as his personal choice to carry on, takes over on Oct. 15. Thile will host 13 weekly shows, split between a fall and winter season, through mid-February. The future of the show beyond that is unclear at this point.
Whether Keillor returns to Tanglewood to perform his solo show also is not yet known.
His health has been a concern following a mild stroke in 2009 and a seizure last month that resulted in a checkup at the Mayo Clinic.
"I feel terrific. Never felt better," he told a Los Angeles public radio interviewer recently. "Everybody has brain episodes, sometimes self-inflicted, and otherwise they just come about. It's a mysterious organ compared to the heart. Neurology is no more a science than, I don't know, astrology or something."
Describing himself as happy about easing out of the hectic weekly demands of live radio to pursue his other projects and relax a bit, Keillor summed up his 42 years with typical understatement: "I think that I've kept people company at a time when they were looking for something. It's interesting to find that you were of use."
Keillor's many admirers are more outspoken. As country music star Brad Paisley put it: "I think he's the Mark Twain of our generation, and that's no small statement."
Contact Clarence Fanto at 413-637-2551.
In their own words ...
"It's simply a matter of wanting to rearrange one's life. In order to do these things, I've got to clear out the big buffalo in the room, which is the show."
— Garrison Keillor
"Johnny Cash once said that true greatness is someone who doesn't remind you of anyone else. That's Garrison. For the past 42 years, he's been the greatest storyteller, the most imaginative voice on the air."
— Actor Martin Sheen ("The West Wing")
"Sometimes people complain that they can't have a conversation with him, but I think that's because he's writing in his head."
— Humorist and friend Roy Blount Jr.
"His gaze is often floating and takes you in from a strange distance. He is certainly the strangest person I know. I don't think he's necessarily a happy man. But the time he is happy is when he is doing his monologue."
— Writer, editor and friend Roger Angell