Sklar was the founding editor of the journal Studies on the Left (Madison, Wisconsin) and the co-founding editor of the weekly newspaper In These Times (Chicago). He contributed essays to Studies on the Left and was the Editorials Editor and sole editorial writer 1976-79 for In These Times. He was a founding editor of the journal Socialist Revolution.; He was an American historian best known for originating the concepts of corporate liberalism, the disaccumulation of capital, and the capitalist-socialist mix. The terms and ideas were introduced in his essays and two books: The Corporate Reconstruction of American Capitalism, 1890-1916: The Market, the Law and Politics (Cambridge University Press, 1988; awarded the James Willard Hurst Prize of the Law and Society Association, 1990) and The United States as a Developing Country: Studies in U.S. History in the Progressive Era and the 1920s (Cambridge University Press, 1992).