The book is a very good read, but it is somewhat light IMHO - I wish it could have been done by Charles Wolfe - I think his book on the Opry "A Good-Natured Riot" is an excellent blend of writing skill and scholarship.
As to the story, A.P. and Sara's story is very sad. Maybelle was a fantastic person - great musician and saved her husband and Johnny Cash from self-destruction. Shame she didn't play the banjo more - she probably would have invented bluegrass before Mr. Monroe.
Chris in Chicago