Conversion has been an essential element of Christianity, and especially of Roman Catholicism, for centuries--from the Apostle Pauls dramatic conversion on the road to Damascus to the spiritual transformations of such prominent modern individuals as Cardinal Newman, St. Elizabeth Ann Seton, Thomas Merton, and G.K. Chesterton. In a 1926 essay, Chesterton expressed reluctance to describe his conversion, on account of a strong feeling that this method makes the business look much smaller than it really is. As David Yamane shows in Becoming Catholic, the business was not only spiritually but literally very large, and growing ever larger: roughly 150,000 Americans join the Catholic Church each year, and more than one in fifty American adults is a Catholic convert. Altogether, these 5.85 million individuals are the fifth-largest religious group in America. In this first significant study of the phenomenon of Roman Catholic conversion in the contemporary United States, Yamane provides an in-depth look at the process of adult initiation in the twenty-first century Catholic Church, including the new process of spiritual formation--called the Rite of Christian Initiation of Adults (RCIA)--that was ushered in by Vatican II. The RCIA process, which has become an integral part of Catholic parish life, takes individuals on a journey through four distinct, formative periods, punctuated by elaborate ritual transitions, before they are finally baptized at Easter. Drawing on years of observational fieldwork and candid interviews with more than 200 individuals undergoing the initiation process, Yamane follows would-be Catholics through all four stages of the RCIA and offers an incisive new perspective on what it means to choose Catholicism in America today.