In this ambitious book, Olson delineates from an evangelical perspective what is and is not authentic Christian belief. Chapters feature such topics as the Bible, God, Jesus and the Church, beginning with an overview of orthodox belief about the topic, citing Scripture, the Church Fathers and noted Christian writers throughout history. Olson then devotes a section to heretical beliefs, and follows this with an examination of diverse non-heretical beliefs among orthodox Christians (including Roman Catholics, Eastern Orthodox believers, and most Protestants). He ends each chapter envisioning greater unity among Christians, despite honest disagreements. Attempting to mediate among the myriad dogmas, doctrines and opinions of orthodox Christians is no easy task, and Olson's descriptions of certain right beliefs and heresies (such as the psychological analogy for the Trinity and modalism) are sometimes barely distinguishable. Despite these and other small logical problems, Olson's book contributes greatly to contemporary evangelicalism not only in its impressive survey of many theologies, but also in its use of "The Great Tradition" of Christian belief as an essential guide to orthodoxy.