On the Folk DJ mailing list a few months ago somebody asked for the 10 people who made the greatest impact on North American folk music. Or something like that. The question was very poorly posed. Here's the nine I suggested, together with one great suggestion that someone made for the tenth. In alphabetical order:

Moses Asch - Folkways Records, getting the music heard A.P. Carter - almost everything Michael Coleman - Irish music in America Bob Dylan - male singer/songwriters Woody Guthrie - political songwriting Robert Johnson - blues, early rock and roll Joni Mitchell - female singer/songwriters Bill Monroe - bluegrass Jimmie Rodgers - country Pete Seeger - the folk revival of the 60s