When, in the 1970's, Sister Prudence Allen, RSM began to investigate philosophical thought on woman, the question was considered to be, at best, a marginal area for philosophical research. Rather, it was seen as a sociological, anthropological, psychological, or political issue. This book confirms that today, partly due to Allen's groundbreaking work, the complementarity of man and woman is an important and fruitful area of research in philosophy providing an evaluative framework that enriches and challenges many other disciplines. No one could have foreseen the centrality of her research for questions of gender theory that are, in the third decade of the 21st century, in the forefront of public attention. In the present volume, leading authors in the area of sex/gender complementarity reflect upon and further develop various aspects of Allen's research. In 16 original, scholarly essays, some contributors build upon Allen's project of exploring "the concept of woman" throughout the history of philosophy. Others explore the work of 20th century philosophers, most of them Christian Personalists, whom Allen credits with significant influence on the development of integral gender complementarity, such as Karol Wojty?a/ John Paul II, Jacques Maritain, Edith Stein, Emmanuel Mounier, W. Norris Clarke, SJ, and Bernard Lonergan, SJ. Still other contributors consider Marian spirituality, analogies between Benedictine spirituality and the physiological realities of a woman's body during pregnancy, seminary education in the writings of Allen and others, and the impact of Allen's work on the real lives of women in families, the Church, and professional life. Upon completing her magisterial, three-volume work, The Concept of Woman, Allen passed the baton to a new generation of scholars, stating, "The next phases will be developed by those who themselves take the argument further and deeper in their own research, writing, living, and lecturing." The present volume takes up the baton, carrying Allen's work forward and paying tribute to the lifetime achievement of a great scholar.