As modest, folksy, and amiable as Garrison Keillor'sPrairie Home Companionstage persona, this documentary is, like the children of his fabled creation Lake Wobegon, "above average." Broadcast onAmerican Masters, the essential PBS biography series, this profile examines "the fortunate life" of the radio host, author, columnist, and humorist, whose iconic old-time radio show ("a museum of broadcasting," he describes it) has captivated millions of listeners for more than 35 years. Short on revelation ("He's a tough nut to crack," one staffer offers), this program instead allows Keillor to expound on why he does what he does and watches him interact with his adoring core constituency, small-town Americans whose work ethic and sense of community are virtues Keillor celebrates on the air and in his writings.The Man on the Radiomeanders a bit, but the leisurely pace suits Keillor.Prairie Home Companionfans will enjoy seeing how the show is put together and putting faces to the voices in Keillor's crack ensemble (a special shout-out to the sound effects virtuosos). Keillor is a performer whose appeal crosses urban and rural as well as blue and red state lines. He offers a weekly respite from contentious (and contemptuous) commentary and political polarization, reaffirming and restoring faith in America's best instincts. "It's  a great country and it wasn't made so by angry people," he states in his best "FM radio voice." The DVD extras offer some additional quality time with Keillor, including an expanded joint interview with Robert Altman, director of the fanciful star-studdedPrairie Home Companionfeature film; a near-40-minute master class Keillor conducted with students of the Savannah College of Art & Design in 2007; and interview outtakes. --Donald Liebenson