In his biography of Charley Patton (written with Gayle Dean Wardlow) Stephen Cal(t) and Wardlow constantly dissed blues artists and Patton contemporaries Willie Brown (the one who did Future Blues and M&O Blues) and Son House in an attempt to elevate Patton, I suppose. Patton is my favorite Delta Bluesman but this seemed odd coming from what you hoped would be at least a fairly objective biography. With all that I immensely enjoyed the book and go back to it now and then.
I'm looking forward to reading the Skip James bio, thanks for the heads-up.