Ted Gioia, Delta Blues (W.W. Norton). Those who think that their musical sophistication places basic blues beneath consideration are likely to benefit from Gioia’s exhaustive, deeply informative study. He concentrates on Mississippi Delta blues and its heroes including Robert Johnson, Son House, Mississippi John Hurt and B.B. King. Gioia traces the evolution of the blues from the plantation work songs that were also one of the roots of jazz. He is persuasive on the role of economics in driving the early bluesmen. He avoids the political and cultural posturing that has flawed some previous books on the subject. This is a welcome, helpful and rly written volume.