Garrison Keillor, as fans of National Public Radio's "A Prairie Home Companion" know, possesses a wonderfully inventive imagination. Every Saturday night ("live from the World Theatre in downtown St. Paul") Keillor emcees an uproariously eclectic musical variety show, delighting a million listeners with his stories, songs and warmly humorous monologues.

Especially popular are his accounts of life in mythical Lake Woebegon, Minn., the home of -- among others -- Bertha's Kitty Boutique, Ralph's Pretty Good Grocery, and the Statue of the Unknown Norwegian. Keillor's creation is a "Spoon River Anthology" with laughs. Lots of them.

But Keillor is no cracker-barrel humorist getting off folksy knee-slappers. His humor is cerebral and complex, a blend of romance and nostalgia; it sparklingly parodies the American (and human) condition. He's also a writer of considerable talent. And though none of his 27 essays and stories (all but three originally appeared in the The New Yorker) concern Lake Woebegon, that shouldn't stop Keillor's fans, or strangers to his work, from enjoying this book.

Away from the microphone, Keillor has more room to develop similar satiric themes and subjects. These, because he's a moralist at heart, focus on the cliche's, media hype and psychobabble permeating American society.

Whatever happened, for instance, to institutions like weddings and buses? In "Your Wedding and You," Keillor's thoroughly pop "Reverend Bob" describes the New Wedding as "Feeling good. Being yourself. Being okay . . . Al and Tammy . . . sharing a commitment to challenge and excitement, were married in 6.12 seconds in Al's Supercharged Funny Car, with a minister on her lap and four bridesmaids on the floor (a new track record)."

And buses? Keillor's Transit Commission-cum-Esalen brochure explains that they're "moving towards a new idea of transit as an experience unto itself, of transit as pure movement. The mystique of transit." It asks, "Why take the first bus that comes along when a bus full of folks who share your interests is coming along a moment or two later? The Book Bus . . . The Senior Bus . . . Ethnic Minority Buses with drivers in colorful native dress. Encounter Buses with probing participants who demand honesty, who will stop the bus and sit there and wait for you to come clean."

Keillor's humor has been called "Upper Midwest," but this label imposes no geographic limitation. Rather, it means his images and perspectives are distinctly American, drawn from its heartland. And this is what makes Keillor so appealing: his extraordinary sensitivity to American voices and icons. His stories and satires glow with a sense of time and place.

He captures the ambiance of a small-town radio station in 1927 (Keillor's only 39), for example, by describing those who sought stardom: "Whistling Jim Wheeler and His All-Boy Band, Elsie and Johnny, 'Ice Cream' Cohen, Norma Neilsen and Fargo Bill, the Orphan Girls Quartet . . . the child elocutionists, yodelers, mandolin bands, gospel-singing families, people who did barnyard sounds and train imitations, and dozens of Autoharp players, all of whom had to be refused, some of them repeatedly."

In "Plainfolks," 12th graders, a' la "Foxfire," seek folk wisdom in their vapid suburb. "Their first real attempt at communication with the older generation" finds them interviewing Dave, who teaches them to blow smoke rings ("It can't really be taught . . . Either you've got it or you don't") and Don, a model railroader who has plans to include in his room-sized 17/64-inch scale layout "high density housing in revitalized inner-city neighborhoods, with industrial nodes shielded by greenways."

And in "The People's Shopper," a takeoff on co-op newsletters, "People's Meats" offers an interim solution for would-be vegetarians: "all of our meat comes from animals who were unable to care for themselves any longer."

Much of "Happy to Be Here" will make you laugh out loud. But several of Keillor's stories are poignant narratives. "The Drunkard's Sunday" is the troubling account of a man's dissolution; "Drowning 1954," Keillor's gentle reminiscense of growing up in a Minneapolis suburb. And in one of his best stories, the narrator is a retired conductor lamenting the loss of The Prairie Queen, "The Jewel of the Plains," a magnificent train destroyed by greed and politics:

"They say she hit the curve at 80 -- some say 100 -- and her wheels screamed as she jumped the track. She dug a double furrow three feet deep in the ground, and flew from the high bank of the Red River . . . and they say on a quiet day if you put your head underwater you can still hear the slow tolling of her bell rocked by the current and the groaning of her joints as she sinks ever deeper in the mud."

Garrison Keillor's fans think he's one of the best things to happen to radio since the transistor. This book should earn him an even bigger audience of listeners and readers.