A handbook-style account draws on decades of investigation to explain communism's ideology, organizational methods, and tactics for infiltrating American institutions. It surveys the movement's structure and discipline, describes underground operations, propaganda, front organizations, and recruitment and financing techniques, and illustrates typical practices used to shape members' beliefs. Interspersed are practical warnings and recommendations for citizens and officials on identifying and countering subversive activity, with emphasis on education, vigilance, and civic resistance rather than sensational anecdotes.