How did a Catholic theologian come to produce the first comprehensive English analysis of one of modern Judaism's most influential thinkers? John Merkle's "The Genesis of Faith" breaks new ground in its systematic examination of Abraham Joshua Heschel's concept of "depth theology"—the study of faith's origins and wellsprings rather than its doctrinal conclusions. Through meticulous analysis of apparent contradictions within Heschel's writings, Merkle reveals faith as a dynamic process of human-divine interaction, emerging from wonder and piety through the interplay of divine grace and human longing. Heschel stands nearly alone among modern Jewish theologians in his dual focus on both conventional theology and depth theology, emphasizing mystery, wonder, awe, and the sublime as fundamental to religious experience. Merkle's unprecedented step-by-step analysis brings new clarity and thoroughness to understanding Heschel's religious philosophy. Beyond its considerable scholarly merit, the work raises pointed questions about why the Jewish academic community failed to fully evaluate Heschel's contributions during his lifetime, even as his posthumous influence continues to grow and his status as a preeminent Jewish thinker becomes increasingly secure.