this is a collection of demoes that Dylan cut for his music publisher, Witmark Music, in New York, between October 1962 and March 1963 (which is when most of them were recorded).
These were done for the publisher to (a) copyright and (b) give to any other act who might be interested in recording them. They weren't meant for public consumption. But they would obviously have been of interest This LP, compiled by the British blues historian Paul Oliver, was one of the most important early collections of 1920s and 1930s blues recordings. It included seminal performances by many of Dylan's early heroes, including Lonnie Johnson, Bukka White, Memphis Minnie, and Blind Boy Fuller. Dylan probably purchased this copy during his December 1962/January 1963 visit to London.