This book, a revision of the author's dissertation, describes the grounds on which knowledge about God is possible according to the Gospel of John. In response to modern questions and doubts about the possibility of religious knowledge, John's answers are identified and illuminated using standard historical method. A major part of this investigation is spent showing that, for readers of all persuasions, it is clear that certain parts of John's Gospel were never intended as either fiction or metaphor. From these parts, the basis on which John thinks that people can have religious knowledge is inferred and described.