The major thesis of this book is presented in the preface (pp. ix-xix). As mentioned in Augustine’s City of God (X 32), the concept of universal salvation was important for Porphyry, “the last and greatest anti-Christian writer” (p. x), and earlier studies have posited a dual soteriology in his works. According to Simmons, however, while Porphyry at first attempted to offer “two distinct ways for the salvation/cleansing of the soul” (p. xii), later he “modified his soteriological system ... to incorporate another way for the cleansing of the lower soul by means of the virtue of continence” (ibid.). Thus in addition to the way for the uneducated masses and that for the mature Neoplatonic philosopher, there is a “third way for the salvation of the soul” (p. xi), and this tripartite soteriological system of Porphyry as presented in the De philosophia ex oraculis was “the closest that paganism ever came to providing a proactive soteriological universalism” (p. xvii) in the period when Christianity was in the ascendant. Christianity nevertheless prevailed, and “one of the major causes of the triumph of Christianity ... was its unique universalist soteriology”. Thus in the history of the Roman Empire, “Constantinian Universalism, with its salient features of One God, One Emperor, and One Empire, took the politico-religious unification policies of preceding emperors to new heights” (p. xix).