A sort of odds and ends collection that was originally issued on LP in 1987, Mississippi Blues, Vol. 4 gathers several alternate takes from Robert Johnson recorded between November 1936 and June 1937, including versions of "Cross Road Blues" and "Love in Vain," eight rare sides recorded by Robert Lockwood, Jr. between 1941 and 1955, and the complete recorded works of Otto Virgil (his actual last name appears to have been "Virgial"), which consists of four sides recorded in Chicago on Halloween in 1925. This set sort of unintentionally traces the migration and changes of the Delta blues as it moved north out of Mississippi and on to cities like Chicago. The Lockwood tracks are actually probably the rarest here, since the Johnson material is all included in the Columbia box, and Virgil's sides show up as single tracks on various other anthologies.