This thesis discusses the history of the closed shop as a form of union security and the changes that arose with the passage of the Taft-Hartley Law in 1947 which declared the closed shop illegal and morally reprehensible.

This study will endeavor to present an analysis of the process in which the National Labor Relations Board gave specific meaning to "interfere with, restrain or coerce" found in section 8(1) of the National Labor Relations Act of 1935. Under Section 8(1) of the Act, the Labor Board, subject to judicial review, has the authority to declare illegal any management procedure which in its opinion involves interference, restraint or coercion.