It's easy enough to dismiss the Highwaymen as representatives of a brand of folk music that has gone out of fashion, at least among the media tastemakers. Their kind of harmony singing, coupled with traditional songs and ballads, has seldom been written of in the decades since their heyday. What's more, their late-'50s collegiate origins, as a quintet whose purpose was to foster entertainment more than to raise consciousness, belonged more to the setting of the hootenanny than the anti-war teach-in or the political rally. They stand alongside the Kingston Trio, the Chad Mitche...