Conversation so far:
When did John Lee Hooker's career begin?
John Lee Hooker was working as janitor in a Detroit steel mill when his recording career began in 1948.
What was John Lee Hooker's first recording?
In 1948 Modern Records, based in Los Angeles, released a demo John Lee Hooker had recorded for Bernie Besman in Detroit.
Was John Lee Hooker's single Boogie Chillen popular?
The single, Boogie Chillen', became a hit and the best-selling race record of 1949.

Question: What genre of music is it?
Self-contained rewrite: What genre of music is John Lee Hooker's single Boogie Chillen?