Labor Czars: A History of Labor Racketeering. By Harold Seidman. (New York: Liveright Publishing Corporation. 1938. Pp. x, 317. $2.50.), The Labor Movement in America. By Marjorie R. Clark and S. Fanny Simon. (New York: W. W. Norton and Company. 1938. Pp. 208. $2.00.) and Labor in Canadian-American Relations. Edited by H. A. Innis. The History of Labor Interaction, by Norman J. Ware; Labor Costs and Labor Standard, by H. A. Logan. [The Relations of Canada and the United States, James T. Shotwell, Director.] (New Haven: Yale University Press. 1937. Pp. xxxviii, 212. $3.75.)