Earth is imperiled. Human activities are adversely affecting the land, water, air, and myriad forms of biological life that comprise the ecosystems of our planet. Indicators of global warming and holes in the ozone layer inhibit functions vital to the biosphere. Environmental damage to the planet becomes damaging to human health and well-being now and into the future--and too often that damage affects those who are least able to protect themselves. Can religion make a positive contribution to this dire landscape of ecological degradation? Schaefer thinks that it can, and she examines the thought of patristic (Christian Church fathers) and medieval Christian theologians to reveal and retrieve insights that may speak to our current plight. Thomas Aquinas provides the architecture as Schaefer builds on themes found in these classic thinkers in an effort to "green" the Catholic faith: valuing the goodness and beauty of creation; respecting creation's praise for God; acknowledging the kinship of all creatures; using creation with gratitude and restraint; and living virtuously within the earth community. In the middle of the book Schaefer offers a case study of the Great Lakes region to illustrate how this approach has a practical application. The final chapter reviews these themes for the models of the human they suggest and focuses on one: the human as a virtuous cooperator, drawn from the teachings of Aquinas. Schaefer's mature and careful analysis helps correct the often-heard criticism that Judeo-Christianity is the cause of the environmental crisis by encouraging "domination" of the world.