Though his long and prolific career is not without a few controversies or justified detractions, and he really only represents one very peculiar slice of the American psyche (cheeky, white-bread, Midwestern Christian, and democrat), Garrison Keillor is an American treasure who deserves every damn one of the comparisons to Mark Twain that he’s ever drawn. The man, who will give one of his signature humorous and rambling talks at the Tobin Center, is like a concentrate of Midwestern life and values, flushed with wit and witticisms, blended with harmlessly wry anecdotes, and topped with light and airy social commentary. He’s got great taste in music, a voice that’s a radio legend in a time when radio legends don’t exist anymore, and a relentlessly creative mind for observational humor and storytelling. Oh, by the way, there are rumors that this may be the famed Prairie Home Companion creator’s last tour, so seeing Keillor live now is like witnessing an endangered species — in more ways than one.