Comparative analysis, especially in the field of religious studies, is widely recognized as among the most difficult of intellectual tasks. How does one do justice to the complexity of both subjects? How does one set the terms of the comparison in a way that accurately captures both similarities and differences? How does one place those similarities and differences in a broader context so that their significance comes to the fore? And how does one present both halves of the comparison in a way that will be equally accessible to readers presumed to be familiar with only one or the other? These challenges are still more formidable when the subjects being compared are “Jewish bioethics” and “Catholic bioethics,” each of which draws on a long ethical tradition, encompasses a wide range of views, and continues to evolve.