It is a pleasant task to thank those who have assisted me along the way. At Cambridge University Press, Beatrice Rehl first expressed interest in the project and Hilary Gaskin carefully guided the manuscript through the review process. Joanna Garbutt helpfully answered many queries, and Jodie Barnes and Anna Zaranko expertly oversaw the production and copyediting phases of this book. The two anonymous reviewers for the Press gave valuable comments.

My home institution provided material support in the form of a 2007 summer research grant and a 2010 fall sabbatical. Colleagues Lawrence Masek, Matthew Ponesse, and Perry Cahall read chapter drafts and offered insightful criticisms in addition to welcome company. On various occasions I have presented versions of chapters, and I am grateful to audience members for their questions and comments. In this regard I owe thanks to William Starr, Gregory LaNave, Carl Still, Brian Shanley, OP, John Knasas, Ed Houser, Mary Catherine Sommers, Christopher Martin, John Hittinger, Michael Waddell, John Finnis, James Jacobs, Nicholas Rescher, Michael Ross, Joseph Murphy, SJ, Jeffery Nicholas, W. Matthews Grant, John Simmons, Timothy Yoder, and Michael Henry.

The librarians at Ohio Dominican University's Spangler Library have been quite helpful, especially Jim Layden, Cathy Kellum, Evelyn Burns, and Joshua Alvarez. I am also grateful to Peter Veracka and Michelle Brown at the Wehrle Library of the Pontifical College Josephinum.

The Philosophy Documentation Center granted permission to incorporate revised excerpts of three previously published articles into the fourth and fifth chapters of this book.