Greeley's major focus is on social concerns within a Catholic framework, such as the responsibility of the church toward the urban poor and the suburban family. Thy Brother's Wife is especially concerned with the roles of women and sexuality in the context of Catholic morality. It focuses on the difficulties, particularly of Irish Catholics, in reconciling the sensual and material pleasures of this world with the spiritual purity and self-denial preached by the Church.

The novel is set nostalgically within the context of John F. Kennedy's years in the White House. In Greeley's eyes, that era marked a confluence of historical events productive of hope and glory for American Catholics. The Irish had been assimilated enough to send one of their own to the White House, and at the same time Vatican II was stimulating waves of renewed enthusiasm within the international Catholic Church. The worldly...