I take it you haven't read the book yourself.

Having spent my professional life as writer and editor, I don't think of "writes pretty well" as any particular recommendation. Yes, Calt was able to frame more or less coherent sentences and get his punctuation marks mostly in the right places. He did possess some musical knowledge (albeit largely squandered in personal vendettas).

The problem is twofold: (1) Calt's manifest loathing of his ostensible subject, Skip James, and (2) the distressing truth that the book actually is about Calt, not about James. It turns out, in other words, to be more autobiography than biography, and not an interesting one at that. There are plenty of excellent books on American blues, folk, and country musicians, written by informed, balanced scholars, critics, and journalists. Names like Paul Oliver, Ted Gioia, Robert Palmer, David Evans, Peter Guralnick, Jeff Todd Tilton, and others come to mind, just off the top of my head. Colin Escott (more concerned with country than blues) delivers his abundant snark with wit and humor. Nobody would ever say that of Calt, who had all the nuance and comic sense of a sledgehammer.