In the early 1950s, my friend Marty Glaberman wrote a pamphlet called “Punching Out,” reflecting on his experience of working in the auto factories of Detroit. Marty later became a professor of labor history at Wayne State University. But when you talked to him or read his writings, it was always clear that he’d gotten the better part of his education from his decades “on the line,”—participating in the constant struggle of workers to retain their humanity as they coped with the unrelenting pace of the assembly line.