A mammoth and important rendering of the Christian faith, by one of the most prominent living Roman Catholic theologians. KÅng (Univ. of TÅbingen, Germany; On Being a Christian, 1976, etc.) surveys Christianity from its origins to the present in a highly readable account that illuminates without being didactic. In an age of confusion about spirituality and the meaning of Christianity, he writes, ``I have not given up hope that it will still be possible to live out Christian faith credibly in the third millennium.'' To redefine Christianity for the future, KÅng looks back; beginning with the ``question of essence,'' he explores attempts by theologians and philosophers to define the core of the religion. For some, like Marx and Feuerbach, all religion (Christianity included) is merely a human projection of psychological needs for something greater than themselves. Others, like Harnack in the early 20th century, sought to discover an ethic rooted in the supposedly pristine teachings of Jesus. Following this review, KÅng discusses the central doctrines of Christianity that are affirmed across denominations (monotheism, the centrality of Jesus as messiah, the workings of the Holy Spirit). The bulk of the volume is devoted to a kaleidoscopic review of the history of the faith from earliest origins to the present. The author views Christian history as a series of paradigm shifts (such as the shift from medieval allegorical scriptural exegesis to Luther's linguistic and grammatical exegesis); these models allow him to discuss differences among various denominations while keeping an eye on what they also share. KÅng does not skirt thorny issues, including papal infallibility, the changing role of women, and the encounter with other faiths. Despite its length, the book doesn't conclude the author's task. This volume is envisioned as part of a trilogy, also covering Judaism (Judaism, 1991) and Islam (forthcoming). Impressive work that could become essential reading for students and interested laypersons alike.