Formed in 1999 and based in North Carolina, the Steep Canyon Rangers are among the most visible and successful bluegrass bands going. Of course, it hasn't hurt that Steve Martin chose them to back him on tour and in the studio (see my review of their Rounder collaboration Rare Bird Alert, which I reviewed in this space on 23 April 2011). Their association with Martin, a banjo player among his other talents, put them on major television shows and in leading concert venues.

The Rangers now move from the small bluegrass label Rebel to the heavy-hitting roots-and-pop Rounder for the first release under their name alone. Those of us who have followed their career know what to expect: well-crafted songwriting from guitarist/lead vocalist Woody Platt, distinctive harmony singing and punctilious, edge-of-tradition picking. On the other side of the bluegrass tradition, a piano appears on one cut ("Easy to Love"), drums on another ("Long Shot"). Whether these portend further artistic exploration to come or are just one-offs remains to be determined.

This is not an outfit anybody would confuse with any other. The Rangers have a signature sound even the bluegrass-unschooled will notice quickly. Their earlier records suggested a unique fusion of modernist bluegrass with doses of earlier Appalachian folk. Nobody Knows You takes the band firmly in the former direction -- tradition only in a broad sense is happening here -- while eschewing any of the paths other bands have taken to get to a post-Monroe sound. One thinks of still-influential outfits once judged progressive -- Country Gentlemen and Seldom Scene, for the most prominent examples -- and the Rangers don't resemble them much at all. Nor do they call to mind the popular, innovative Blue Highway.

Instead, the Rangers have found a signature approach, employing an adventurous musicality -- not to mention a creative notion of what bluegrass lyrics can be -- that at once affirms and challenges the genre's boundaries. One suspects (or contemplates uneasily) that future discs will be more challenge than affirmation -- unless, of course, the Rangers take an abrupt right turn and put out a disc of traditional material done their way. Now, that would be interesting.

Make no mistake. This is bluegrass, specifically a smart bluegrass that's redefining itself for a world daily less like the one in which Bill Monroe, a modernist in his time, first envisioned how the Old Southern Sound could be reinvented for the Grand Ole Opry stage and the new recording technology. Happily, the musical sons and daughters of Monroe and the Stanley Brothers continue to produce worthy bluegrass in that sturdy neo-oldtime style. Just as happily, the Rangers administer a jolt of 21st-century possibility into the genre.