Recent scholarship on gender and religion in colonial Spanish America has increasingly considered subjects and regions previously neglected. Thanks to these efforts, we are beginning to trace a more accurate picture of how the lives of the majority of women were affected when coming into close contact with the Catholic Church. By studying non-elite lay female religiosity and the ways in which it shaped local religion in Guatemala, Alone at the Altar represents one of these efforts. Brianna Leavitt-Alcántara uses a variety of sources in her book, yet the core of her study relies on her analysis of 539 wills produced in 13 selected years between 1700 and 1870, in which she finds invaluable information about religious mentalities and practices. The book is divided in two parts: Part 1, with three chapters, focuses on the period between 1670 and 1770; and Part 2, also with three chapters, looks at the years between 1770 and 1870.

Chapter 1 analyses the experiences of Ana Guerra de Jesús, whose spiritual biography was published by a Jesuit priest after her death in 1713. Ana was not a cloistered nun, but rather a poor abandoned wife and mother, and yet her religious experiences were considered worthy of praise and admiration by the local church and lay community. Leavitt-Alcántara uses the life of Ana as a starting point to reconstruct the religious landscape of Guatemala City, including valuable information such as the numbers of churches, priests and brotherhoods that existed in the city. Chapter 2 explains the active promotion of the lay tertiary path for single women in the hands of the Franciscan order as a phenomenon that responded to the social and cultural context of Santiago de Guatemala. The author notes how in some instances both Franciscans and Jesuits worked together to encourage this kind of religiosity in lay women, and that Ana's spiritual biography was most likely conceived as propaganda to encourage lay women's religiosity since it provided a model of lay piety. Chapter 3 argues that non-elite, unmarried women were successful in navigating the religious landscape of Guatemala by becoming increasingly involved in the spiritual economy as pious benefactors and allies to local priests. Moreover, the author traces the ways in which these women's wills invoked feminine ideals that differed from the traditional notions of chastity and enclosure. As donors and active members of confraternities and brotherhoods, non-elite, single women shaped local religion and claimed a form of religious authority.

Part 2 opens with a brief narrative that explains the chronological divide of the book by pointing to the devastating earthquake of 1773, and the newly arrived captain-general's controversial decision to move Guatemala's capital to a new location, leaving Santiago as the old city or ‘Antigua’. Chapter 4 centres on the three schools for girls that opened between 1780 and 1795 in Guatemala City, and more specifically on the role that lay women had in shaping education through engagement with enlightened ideals and Catholicism. Lay women took an active role in reforming education and expanding it to poor, mixed-race and indigenous girls. These schools sought to provide not only basic education but also training in activities that would be productive in economic terms. There was more emphasis on useful knowledge like sewing and making cigars, and less on learning music, for example.

Chapter 5 is the only one dedicated to a religious woman, Sister María Teresa Aycinena, a Carmelite nun whose mystical experiences attracted the attention of religious authorities and the political criollo elite in the early nineteenth century. She was a controversial figure who, through affective spirituality, gained authority and found herself in the middle of a political controversy after Independence. The author argues that Sister María Teresa's mystical experiences were interpreted as a sign of God's favour of criollo resistance. While the nun didn't declare political allegiance to either party, her family and her followers were involved in the independence-era political strife. Just as in Mexico, this period saw a renewal of affective piety and miraculous cults in which Sister María Teresa took the lead.

Chapter 6 considers the period after Independence, and the newly created devotional opportunities that allowed non-elite, single women to take a leading role in rebuilding the Church. The promotion of a Marian feminine ideal of sexual purity and the dramatic decline of confraternities presented challenges for working-class women, yet the prominent role that they took in battling anti-clerical legislation granted them moral status and spiritual authority. The book ends with a brief epilogue that recounts the political changes that Guatemala has undergone in the years between the 1865 fall of the conservative government and the present, highlighting the ways in which political changes have affected the religious landscape of Guatemala and the options that single women have found in the Church.