In the early years of the Great Depression the Marine Workers Industrial Union was a colorful presence on the American Waterfront. In 1935 the MWIU seemed to vanish, closing its halls and stopping its publications. The author convincingly demonstrates that the MWIU did not vanish, instead it was ordered by the Moscow based Communist International to send its members into mainstream ALF unions and take over from the inside. Deliberately duplicated on the east coast, the Communists succeeded in destroying the International Seamen’s Union and creating the Communist dominated National Maritime Union.