Sunday, January 23, 1921, midtown Manhattan, the Lexington Theater. It was a good day to watch a fight. A packed audience attended the sold-out event. An estimated 3,500 were in the theater, while others sought out tickets, at a stiff markup, from hawkers on the sidewalk. Was this a boxing match? A wrestling bout? An exhibition of martial arts? No, this was to be a battle between two economics professors, a three-round debate on a weighty topic on everyone's mind: capitalism versus socialism. On one side of the debate was the Progressive establishment figure, E.R.A. Seligman, Chair of the Economics department at Columbia. On the other was Scott Nearing, radical activist, enfant terrible, and professor at the Rand School of Social Science. Their debate was called the "debate of the decade" and garnered wide attention. Alongside an annotated transcript of the debate itself, Rob Weir describes the personal and historical background of the debate, provides round-by-round analysis of the debate arguments, and concludes with detailed coverage of contemporary reactions to the debate.