<p> When Steve Martin surfaced on stage in the '70s with a banjo, many thought it was a gag, a funny prop. But as glimpsed in the intro to director Marc Fields\' documentary <em>Give Me the Banjo</em>, Martin is an able musician who takes his instrument seriously. He narrates this history of the banjo, which began in Africa with gourds and strings and went through several permutations after its forced transplant to the New World. </p> <p>“A complicated and checkered past,” as Martin says, and <em>Give Me the Banjo</em> (out on DVD) surveys much of it. The instrument became the hallmark of minstrelsy, the 19th century precursor to white-boys-sing-the-blues, a genre whose subversive escape from the confines of WASP propriety was never entirely separate from its mockery of African Americans. During the 1920s the banjo was heard on the early string band recordings that laid the stones for country music. And yet for many, it never entirely shed its image as instrument of choice for clowns and bumpkins. </p> <p>Post-World War II, the banjo was taken down two paths, one by Earl Scruggs, who came to it with mother's milk, and the other by Pete Seeger, the patrician folklorist who donned a work shirt and hitchhiked the South in search of authenticity. Seeger helped spark the folk music revival, whose unanticipated child, Bob Dylan, changed the face of rock in the '60s. Scruggs showed how the banjo could be an instrument for virtuosity, pointing the way to Bela Fleck. </p> <p><em>Give Me the Banjo</em> includes much archival footage and interviews with Pete and Mike Seeger, Tony Trischka and many others. </p>