The history of Christianity and particularly of Roman Catholicism has been profoundly shaped by conversion for centuries, from the first apostles to such prominent modern converts as John Henry Newman, St. Elizabeth Ann Seton, G.K. Chesterton, Thomas Merton, and Graham Greene. Each year, approximately 150,000 Americans convert to Roman Catholicism. Catholic converts collectively are 2.6 percent of the U.S. adult population; together these 5.85 million individuals would comprise the fifth largest religious body in America, just behind the Mormon Church. In Becoming Catholic, David A. Yamane offers the first book-length study of Roman Catholic converts in contemporary America. The process of adult initiation in the 21st century Catholic Church looks very different than it did 50 years ago. One of the many revolutionary products of the Second Vatican Council was a revised process of initiation called the Rite of Christian Initiation of Adults (RCIA). The RCIA process takes individuals on a journey through four distinct periods of formation, with elaborate ritual transitions that carry individuals from period to period. Drawing on six years of observational fieldwork and interviews with more than 200 people undergoing the conversion process, Yamane follows converts through each stage of the RCIA, shedding light on what it means to choose Catholicism in contemporary America. Becoming Catholic offers a window onto the transmission and transformation of the Catholic tradition in a pluralistic and voluntaristic, twenty-first-century society, illuminating a critical aspect of American Catholicism and American religion at the outset of the third millennium.