A lot of the famous U.S.Labor and Work songs of the first half of the twentieth century were associated with The Industrial Workers of THe World or Wobblies a socialist/syndicalist organisation which produced numerous editions of their Little Red Song Book containing words,music and history of the songs. The I.W.W. still exists and I think you can still get the latest edition from them -they have a website which might be a good place to start. Si Kahn is a modern writer who has written some fine songs about work and labor issues.