The Cardinal Sins shocked many with its tortured, bisexual archbishop, whose encounters with women are invariably brutal. Thy Brother's Wife … is in fact a better, more hopeful book. The pace is quicker, the characters more firmly drawn, the sexual rites gentler. Greeley's turf remains Camelot West: the Chicago of lace-curtain Irish who have pushed their way to the top. Multimillionaire Mike Cronin, who beds women faster than Joe Kennedy could say "Gloria Swanson," has set the course for his two sons. Paul, the Notre Dame boy who goes off to win a Medal of Honor in the Korean War, is going to be President. Sean is bound for the priesthood, and will of course be a Cardinal. Paul's wife is to be Nora, orphaned daughter of a family friend and a foster child in the Cronin home. Sean loves her; Paul gets her, hence the temptation of Thy Brother's Wife.

Everything moves fast for the Cronins—even tragedy. (p. 70)

Sean's fate seems to be Greeley's fantasy. He is ordained at St. Mary of the Lake Seminary in Mundelein, the author's alma mater, in 1956, just two years after Greeley was. Greeley remembers being "very cautious, very conservative. I kept all the rules." So does Sean. Assigned to a black parish (unlike Greeley), he works himself to near collapse. A new archbishop sends the exhausted curate off to Rome to study the history of church marital theology, and Sean finds himself on the famous papal birth control commission, where he stubbornly decides to abstain from voting. The move wins him an interview with Pope Paul VI, whom he lectures about the need for a new theology of sexual morality. Sean could use it himself: he has just spent two weeks in bed with Nora. Neither the interlude nor a brash period of liberalism prevents his rise, however, first to bishop and then, after a telephone call from Pope Paul, to Cardinal Archbishop of Chicago.

Sean's triumph is something more than diverting summer fiction for Greeley. For years he was an outspoken foe of the late, scandal-plagued Archbishop of Chicago, John Cardinal Cody…. Assuming Cody's position would be the ultimate revenge. That is a basic problem with Thy Brother's Wife: its mean streak. Most of the tragedies in the novel result not from too much lovemaking but too much getting even. Perhaps this is less a reflection of Greeley's art than of his anger. There are many Andrew Greeleys, and there are clearly two working at cross-purposes here: Greeley the romantic, wishing that life could be full of grace, and Greeley the realistic priest, who knows how dark human souls can be. The priest keeps trying to explain, but it is the bitter romantic who keeps getting even. (pp. 70, 72)