The Second Vatican Council (1963-66) asked Catholic sisters to adapt their rules to modern culture. To help religious communities discern what should be kept, and what discarded, Sister Ewens undertook this study of church decrees of the past and their influence on the present. She also analyzed sisters' roles in nineteenth-century U.S. society, their actual roles as teachers, nurses, etc., and those depicted in the popular media (often stemming from anti-Catholic bigotry.) When this ground-breaking book was published in 1978, it became the cornerstone of all subsequent research on women religious in the U.S.

Ewens documents immigrant sisters' adjustments to American mores, their problems with bishops, their economic challenges, sisters' attempts to live according to medieval rules in pioneer settings; their contributions to education, nursing, and social services; their encounters with bigotry; how they transformed the public image of Catholicism; the ways they supported themselves; and much, much more. Vatican officials who question U.S. sisters' roles today could learn from this book why sisters' lives had to evolve in response to the call of the Council.