The "Who's Who in Labor" published by the Dryden Press in 1946 was billed as the "authorized biographies of the men and women who lead labor in the United States and Canada and of those who deal with labor...." Created through the cooperation of the AFL and the CIO, the single volume also includes separate directories of labor periodicals and union education directors.
WorldCat listing: http://ucla.worldcat.org/oclc/772456
Only the files for the labor press listing are available at this time.