"What's Good is a work of passionate lyrical analysis, a set of freewheeling liner notes, and a love letter to the most vital American art form of the last half century. Over a series of short chapters, each centered on a different lyric, Daniel Levin Becker considers how rap's use of language operates and evolves at levels ranging from the local (slang, rhyme) to the analytical (quotation, transcription) to the philosophical (morality, criticism,...