Essential R&B - Summer 2010, an album by Various Artists 　　 　　 　　Essential R&B: Summer 2010, released by Rhino U.K., entails not just R&B but R&B-leaning pop, rap, and dance-pop that bears little relation to rhythm and blues. While the selections are mostly up to date, some of them reach back a couple years (John Legend’s “Green Light” and Jennifer Hudson’s “Spotlight,” for instance). Among the more popular songs included here are Usher’s “OMG,” Alicia Keys’ “Try Sleeping with a Broken Heart,” Alexandra Burke’s “Broken Heels,” and Chipmunk’s “Look for Me.” All in all, a decent, if somewhat random, round-up of major charting U.K. singles circa mid 2010.