small religious groups that lack in organization and emphasize the private nature of personal beliefs. Later sociological formulations built on such characteristics, placing an additional emphasis on cults as deviant religious groups, "deriving their inspiration from outside of the predominant religious culture." This is often thought to lead to a high degree of tension between the group and the more mainstream culture surrounding it, a characteristic shared with religious sects. According to this sociological terminology, sects are products of religious schism and therefore maintain a continuity with traditional beliefs and practices, whereas cults arise spontaneously around novel beliefs and practices. In the early 1960s, sociologist John Lofland, living with South Korean missionary Young Oon Kim and some of the first American Unification Church members in California, studied their activities in trying to promote their beliefs and win new members. Lofland noted that most of their efforts were ineffective and that most of the people who joined did so because of personal relationships with other members, often family relationships. Lofland published his findings in 1964 as a doctoral thesis entitled "The World Savers: A Field Study of Cult Processes", and in 1966 in book form by Prentice-Hall as Doomsday Cult: A Study of Conversion, Proselytization and Maintenance of Faith. It is considered to be one of the most important and widely cited studies of the process of religious conversion. Sociologist Roy Wallis (1945–1990) argued that a cult is characterized by "epistemological individualism," meaning that "the cult has no clear locus of final authority beyond the individual member." Cults, according to Wallis, are generally described as "oriented towards the problems of individuals, loosely structured, tolerant [and] non-exclusive," making "few demands on members," without possessing a "clear distinction between members and non-members," having "a rapid turnover of membership" and as being transient collectives with vague boundaries and fluctuating belief systems. Wallis asserts that cults emerge from the "cultic milieu". J. Gordon Melton stated that, in 1970, "one could count the number of active researchers on new religions on one's hands." However, James R. Lewis writes that the "meteoric growth" in this field of study can be attributed to the cult controversy of the early 1970s. Because of "a wave of nontraditional religiosity" in the late 1960s and early 1970s, academics perceived new religious movements as different phenomena from previous religious innovations. In 1978, Bruce Campbell noted that cults are associated with beliefs in