The last time that eclectic one-man band Keller Williams combined with Larry and Jenny Keel on record, for 2006's Grass, they came up with bluegrass arrangements of songs by Pink Floyd and Tom Petty along with their originals. For this follow-up, they have taken an all-covers approach, as the title Thief is meant to suggest. Once again, they are borrowing from rock and working up versions that feature the flatpicking of Williams and Larry Keel over Jenny Keel's bass, resulting in a humorous effect when applied to, say, Amy Winehouse's "Rehab." Some songs are already humorous on their own, such as Patterson Hood's "Uncle Disney" and Cracker's "Teen Angst," the latter also representing a subgenre of songs on the album, favorites from 1990s acts like the one-hit wonders Marcy Playground and Butthole Surfers. In other cases -- Ryan Adams' "Cold Roses," the Grateful Dead's "Mountains of the Moon," the Yonder Mountain String Band's "Wind's on Fire," and the Raconteurs' "Switch and the Spur" -- the originals already had something of a bluegrass flavor. Keller & the Keels play with their tongues in their cheeks, but that doesn't mean the music itself is lacking in virtuosity. On the contrary, the humor tends to put the players' musicianship in the back seat, even though the jokes wouldn't be so funny if they weren't doing some high-quality picking here. It's just that they're doing so while maintaining their sense of humor and paying affectionate, if not entirely sincere, tribute to some of the music they love.