During his long tenure as director of the Federal Bureau of Investigation, J. Edgar Hoover made no secret of his high regard for the Catholic faith. Though himself a Protestant, he shared with Catholicism a set of values and a vision of the world, grounded in certain assumptions about the way things ought to be in a well-ordered society. The Church reciprocated Hoover’s admiration, establishing the basis for a working alliance between two powerful and influential American institutions. Steve Rosswurm explores the history of that relationship from the turbulent 1930s to the 1960s, when growing Catholic opposition to the Vietnam War led Hoover to distance himself from the Church. Drawing on a vast range of sources, including thousands of pages of previously classified FBI files, Rosswurm pursues his investigation along two parallel tracks. First, he looks at the joint war waged by Hoover and the Catholic hierarchy against forces considered threats to their organizations, values, and nation. Second, he examines how each pursued its own institutional interests with the help of the other. While opposition to communism was a preoccupation of both institutions, it was not the only passion they shared, according to Rosswurm. Even more important, perhaps, was their fervent commitment to upholding traditional gender roles, particularly the prerogatives of patriarchal authority. When women and men carried out their assigned obligations, they believed, society ran smoothly; when they did not, chaos ensued. Organized topically, The FBI and the Catholic Church, 1935–1962 looks not only at the shared values and interests of the two institutions, but also at the personal relationships between Hoover and his agents and some of the most influential Catholic prelates of the time. Rosswurm discusses the role played by Edward A. Tamm, the FBI’s highest-ranking Catholic, in forging the alliance; the story behind Father John Cronin’s 1945 report on the dangers of communism; the spying conducted by Father Edward Conway S.J. on behalf of the FBI while treasurer of the National Committee for Atomic Information; and Monsignor Charles Owen Rice’s FBI-aided battle against communists within the CIO.