Davis, an assistant professor of history at the University of Delaware, has written a deeply researched and readable work. She demonstrates how, during the 1930s, a small but powerful group of reformers introduced the concept of marriage counseling and guidance. They emphasized strong marriages as the bedrock of individual and societal health.

Consequently, over the course of the 20th century, Americans’ attitudes about what makes a successful marriage changed. It wasn’t enough simply to avoid the “failure” that divorce represented; now couples aimed to achieve “mutually beneficial emotional, financial and sexual gratification.”

Leading in this evolution of attitudes were many religious institutions, including the Catholic Church, which Davis discusses in some detail. Assuming the mission of strengthening their congregants’ marriages gave clergy a newfound relevance in the 20th century. For Catholics, of course, marriage is a sacrament, a visible sign of grace. In the 1940s and 1950s, Catholic leaders and theologians devoted increasing attention to the sacramental nature of matrimony.

When the first major Catholic marriage counseling center opened in 1952 at The Catholic University of America, it aimed to provide a thoroughly Catholic alternative to more secular marriage guidance that might emphasize, for instance, artificial birth control. In 1953, Davis notes, the center provided guidance to more than 1,000 couples and trained 500 clergy and laypeople as marriage counselors.

“More Perfect Unions” offers plentiful historical context. For instance, we learn that the theological weight given to Catholic marriage developed just when Catholic families were moving out of their ethnic, inner-city parishes into the suburbs. From about 1920 to 1960, Davis writes, “marriage loomed larger in American Catholic life as suburbanization removed Catholic families from the thick kinship networks of their urban parishes and transformed religious communities into dispersed nuclear units.”

Many more insights await the reader in this gem of a study, rich with detail culled from case histories, personal letters and many other archival sources.

In “What I Wish Someone Had Told Me About the First Five Years of Marriage,” Roy Petitfils offers succinct, practical tips aimed especially toward the newly married. The Catholic counselor at St. Cecilia School in Broussard, La., and at Pax Renewal Center in Lafayette draws from his own marriage experiences and those of his clients and friends. “The first five years of marriage,” he writes, “should be the first of many years together.”

Squarely grounded in contemporary Catholic thought, Petitfils asserts that “a joy-filled life together is not only possible but it is in fact what God intended for marriage.” To get there, he suggests a combination of prayer, scriptural reflection, communication and action.

The book emphasizes that essential ingredients in a successful marriage are the partners’ respect for each other, common values, the ability to talk openly about what happens between each other, the ability to compromise and a readiness to forgive.

A natural storyteller, Petitfils makes his advice memorable with some humor. For instance, he suggests that, when in the midst of marital conflict, spouses try to follow “bee yard etiquette.” This means “Be gentle, speak softly, and don’t swat, physically or verbally.”

Individual chapters focus on topics such as sex and Christian marriage, money (“the real American idol”), parenthood, relationships with in-laws, time management, and balancing individual and couple spirituality. Although brief, the book offers much practical advice that will aid both newlyweds and couples of many years.

Roberts directs the journalism program at the State University of New York at Albany. Her books include “Dorothy Day and the Catholic Worker.”