Reid begins Power over the Body with a modern, secular view of marriage which is "at will," individualistic, and laden with partner rights. St. Augustine clarifies at the end of the Roman Empire that marriage "sought to conserve three great goods—the procreation/education of offspring, fidelity between the parties, and lifelong unity" (pp. 9-10). While painting a broad picture in the beginning, Reid's writing takes on minute details not far into the introduction. With a proclaimed "narrower focus" than other books tackling the same subject, "a close consideration of the use of rights language in the formation and living out of the marital relationship" is the main goal here.

The first portion of the book is devoted to marital rights, including opposition by blood families, coerced consent, and other forms of parental involvement. It is the breaks with tradition here that are explored in greatest detail. In particular, the right and freedom to contract marriage is illustrated by the compelling story of Christina of Markyate, who even upon marriage, maintained her vow of virginity, remaining chaste as a bride of Christ. With this example, a vast number of questions are raised about the rights of parents, the rights of the church, the rights of the parties to the marriage themselves, the nature of conjugal debt, and the power of religious life to dissolve a marriage. We learn of what it takes to give a child away to marriage at the age of seven and above, what rights that child has if the parent or guardian is determined insane, and other questions of legal import. As expected, there tend to be more rules of a stricter sort for female children than for male children, though they are somewhat relaxed as we move through the centuries. We finally get to a place where Raymond of Penafort noted that "the law made clear that coerced matrimonial consent was no consent at all" (pg. 47). At length, we are then educated on "clandestine marriage" (pp. 50-63) as a tool for asserting matrimonial freedom.

Next, we turn to governance via parents. This is basically an assessment of family paternalism. The man has ultimate power over his wife and his children (including life and death decisions). In illustration, Mary was "presumed to have subjected herself to Joseph's benevolent authority" (pg. 75). This is laid out as a clear exception to medieval domestic relations. The normal paternal power could not be used indiscreetly, however. "Exposing a child" amounted to criminal misconduct on the part of parents, for example (pg. 97). Such power must always contribute to the fabric of the family unit (rather than the contrary, tearing that unit to pieces). Hence, moderation was taught in all aspects of discipline.

The middle of the book turns to women's rights. Mainly in terms of spiritual, conjugal debt ("owing"), justified divorce, and (oddly) burial rights were women granted relationship equality. Still, females were subjected to harsh treatment and often unrealistic expectations as a part of the marital dyad. In fact, it was stated that the right of the woman was of "diminished condition," due to their being "subject to male headship" (pg. 103). However, the woman does maintain certain power. A marriage, for instance, was not recognized until consummated with sexual relations, and for this, the woman had two months to decide after the wedding if she would instead enter a religious life for which she must remain chaste. Still, "the husband is the head of his spouse and, "as it were, her reason and her good judgment" (quasi ratio et consilium). The man was created in the image and likeness of God, and the woman was created in the image and likeness of her husband" (pg. 150). However, this is softened with the assertion that woman was created from man's side, "not his foot," so she would be his associate and not his slave. The law is seen as a product of this insight into at least some form of "theoretical" equality (pg. 151).

The final section discusses offsprings' natural inheritance rights (when they are "true" relations born in a "marital union"—pp. 209-210). Their "claim owing by nature" (pg. 23) as well as their obligations are outlined in terms of medieval understanding. Basically, the canonistic system is based on a "Christian vision of family that expected rights to be exercised against a backdrop of mutual and reciprocal love" (pg. 154). The fact that medieval marriage reflected an ordered structure is emphasized throughout the entire book, and is especially emphasized here.

Finally, rights in the context of domestic relations law (pp. 211-213) are discussed at some length in terms of John Stuart Mill's On Liberty individualistic approach versus traditional Catholicism's focus on obligation and duty toward others, over and above any personal interest.

The book's work can be summarized as an historical reconstruction of medieval canonical law. What is illuminated throughout the volume is that "a logic of rights compels particular results" (pg. 213). In short, the approach is one of extreme details, sometimes to the detriment of the larger picture of the historical period that Reid is attempting to convey.