Almost forgotten now, his name known only to blues aficionados, Sonny Boy Williamson practically invented the use of the harmonica as a solo instrument and was known as the father of the modern blues harp. Born near Jackson, Tennessee, in 1914, he began recording in 1937 for the RCA subsidiary label, Bluebird Records. He played on literally hundreds of records, accompanying other musicians and leading his own sessions, and he became very popular during the 1920s and '30s.

A prodigy, he wrote the classic blues tune, "Good Morning, Little School Girl" when he was 12. Among his other classic compositions are "Sugar Mama Blues," "Shake the Boogie," "Sloppy Drunk" and "Hoodoo Man Blues." His music influenced many other blues harpists, including Billy Boy Arnold, Junior Wells, Sonny Terry, Little Walter and Snooky Prior. Rice Miller was so carried away by Sonny Boy's music that he stole his name, also billing himself as Sonny Boy Williamson.

Mitsutoshi Inaba's book is the first full-length study of Williamson and his music. It is not, strictly speaking, a biography, but instead closely examines Sonny Boy's harmonica style, looking at the songs he wrote and recorded and figuring out elements of his style and which techniques are being used in each. The book uses prose descriptions and musical notation to get across the figures and solos Sonny Boy plays. In order to get his musical transcriptions right, the author even learned to play the blues harp as part of his research. As a result, his descriptions can get pretty technical. Here is a part of his discussion of "Good Morning, Little School Girl."

Sonny Boy plays an F-harmonica in the key of C. ... The hornlike motive gives the composition a recognizable character. Here (measures 1-2) he starts from from a combination of two techniques -- playing two notes simultaneously (holes 2 and 3) and pitch-bending (hole 3: E is bent to E-flat). The passage rests on B flat (measures 2 and 4: hole 2) with another pitch-bending technique.

And so on. Inaba describes almost every record Williamson cut in this manner. If you know harp or if you know a little about musical terminology, you're OK. A casual reader, however, is liable to get lost in the technical.

Sonny Boy Williamson learned his music and built his career in the South, playing mostly country blues, but as he progressed on his instrument, he found himself getting more urban; playing louder, faster, more aggressively. He experimented with amplifying his harp -- a method Snooky Prior gets credit for inventing -- by holding a microphone close to the instrument as he played, a technique that became the norm in the hands of Little Walter and Junior Wells. Although he played through an amp in live appearances he never recorded with amplification. All of his records feature an acoustic harp. In 1942, feeling his new style of music would be better received in the North, he move to Chicago, to the Bronzeville neighborhood on the South Side.

Although Bronzeville offered a number of places to play and the companionship of other musicians, it was a dangerous neighborhood: Sonny Boy Williamson was mugged and killed walking a few blocks home from a gig at the Georgia Club.

Inaba's book is more about the art of Sonny Boy Williamson than his life, gives only a bare-bones biography while concentrating on his music. It is meticulously researched; he has listened to all the records enough times to identify the ways in which Williamson achieves his effects on each one, has read the stuff about his subject's life and career, and has talked to the surviving musicians who remember him. His text is about 150 pages, followed by a discography and almost 30 pages of notes. Inaba's book will remain the standard examination of the work of Sonny Boy Williamson.