This Companion offers an overview of the beliefs, doctrines, and practices of the key philosophical concepts at the heart of Christian theology. The sixteen chapters, commissioned specially for this volume, are written by an internationally recognized team of scholars and examine topics such as the Trinity, God's necessary existence, simplicity, omnipotence, omniscience, omnipresence, goodness, eternity and providence, the incarnation, resurrection, atonement, sin and salvation, the problem of evil, church rites, revelation and miracles, prayer, and the afterlife. Written in non-technical, accessible language, they not only offer a synthesis of scholarship on these topics but also suggest questions and topics for further investigation.