I was asked to co-author a book for Hal Leonard Publications that would make the guitar music of Robert Johnson available for banjo players.  Dave Rubin, blues guitar expert and author of several blues guitar tab books, had already transcribed the material as it was originally played on guitar.  My work was to transfer the exact arrangements to banjo. It was a year in the making and is now available:

Robert Johnson for Banjo, by Dave Rubin and Lydia Sylvia Martin. Hal Leonard Publications.