Four solo albums in, Beyonce's earned the right to experiment. And 4 is a bold, risky test of the parameters of 2011 pop stardom. Eschewing the day's dance trends (and really, club-ready tracks in general), Beyonce spends most of the album growling through gut-punching slow and mid-tempo jams steeped in solid-gold '70s soul and '80s R&B (think synthy horns and Prince, not robo-disco). Then there's a militaristic march that culminates in the post-apocalyptic "Run the World." In short, there may not be a smash single in the bunch -- and it might be some of Queen B's most interesting work ever.