Many people believe in angels and evil spirits, and popular culture abounds in talk about encounters with such entities. Yet the question of the existence of such spirits is ignored in the academy. Even the Christian Church, which one might expect to show keen interest in transcendent realities, does not appear to be paying much attention. In this book Phillip Wiebe defends the plausibility of the traditional Christian claim that spirits are real. Wiebe examines descriptions of encounters with both good and evil transcendent beings in biblical times and in later Christian history, along with recent accounts of similar experiences. He argues that invisible beings can be postulated to explain events just as unobservable objects are postulated in many scientific theories. Beyond supporting claims for the existence of lesser spirits such as demons and angels, this empirical approach yields important results for assessing common arguments surrounding the existence of God - a question that has become artificially separated from the question of spirits as such. Grounding his argument in a wide range of phenomena - from near death experiences to demonic possession - Wiebe offers a sophisticated case for belief in God on philosophical and epistemological grounds.