Published in honor of John C. Olin, Professor Emeritus of History at Fordham University, for his many contributions to the study of Catholic reform in the sixteenth century, this is an assembly of nine essays on Catholic religious orders of that period. The contributors devote attention to the spirituality of the founder(s) and to the specific apostolate of the order. The focus of the essays is on the religious communities that were founded between 1524, when the Theatines arose, and 1621, when the Piarists were recognized by the papacy as a religious order. Most of these orders were founded for reasons unrelated to the crisis posed by Protestantism, but they were soon enlisted by the hierarchy to counteract its effects. If the Council of Trent (1545-1563) can be considered the architect of Catholic reform and renewal, and the papacy and episcopate as its enforcer, surely the religious orders of men and women in the sixteenth and early seventeenth centuries ought to be considered as the initiators or disseminators of reform while serving as missionaries, teachers, preachers, catechists, and confessors. The contributors are: Kenneth J. Jorgensen, S.J., Albertus Magnus College; Elisabeth G. Gleason, University of San Francisco; Richard L. DeMolen, Erasmus of Rotterdam Society; Charmarie J. Blaisdell, Northeastern University; John W. O'Malley, S.J., Weston School of Theology; Jodi Bilinkoff, University of North Carolina-Greensboro; John Patrick Donnelly, S.J., Marquette University; Wendy M. Wright, Creighton University; Paul F. Grendler, University of Toronto.