Mandolin player and singer Chris Thile's band Punch Brothers may have a standard bluegrass lineup also including a guitar, banjo, fiddle, and bass, but if their music fits into the bluegrass category at all, it's only because of that instrumentation.

On their debut, Punch, and this follow-up, Antifogmatic (said to be a word referring to a 19th century alcoholic drink thought to be a cure for bad weather), Punch Brothers play in a style beyond the "contemporary bluegrass" or even "newgrass" tags; "progressive bluegrass" (as in "progressive rock") might be closer to the mark, or even "avant-garde bluegrass." On Punch, Thile introduced a four-part, 40-minute suite called "Blind Leading the Blind." If nothing on Antifogmatic is quite that ambitious, nevertheless in track after track Thile leads the band through labyrinthine arrangements that shift tempos and instrument groupings, over which he sings abstract lyrics in a slightly disembodied high tenor voice.

It all has the quality of a dream or, on the cosmically comic "Next to the Trash," of novelty music.

By the end, in "This Is the Song (Good Luck)," Thile is acknowledging current economic challenges in a way that recalls the Depression Era origins of bluegrass, as he sings, "These are tough times, but we'll get by." It's an unusually down-to-earth sentiment after an album full of music and words that have seemed up in the clouds (or lost in the fog).