He is particularly associated with research into the lives of the musicians Charlie Patton and Robert Johnson and the historical development of the Delta blues, on which he is a leading authority.
However, by about 1960, he had started collecting blues records for their own sake and realized that very little biographical information existed on the musicians who had created them.
[1] By 1963, Wardlow had begun researching a book on Delta blues musicians, mainly by making enquiries in black neighborhoods, recording oral histories, anecdotes, songs, and remembrances.
He interviewed Ishman Bracey, Charlie Patton's widow, and blues talent broker H. C. Speir,[2] and a few years later, uncovered Robert Johnson's death certificate.
He also amassed the world’s largest and most valuable collection of pre-war blues records, many of which are now unique.