Abstract: Different theologians give different accounts of the kind of faith that is necessary for the practice of a religion such as Christianity. For some it is simply belief that there is a God (and that he has done various actions); for others it is trust in God. This book analyses the nature of belief and trust, and considers when belief and trust are rational. It concludes that the practice of a religion requires a faith which involves both trust and belief, but a fairly weak kind of belief. The book reaches this conclusion by analysing the purposes for practising a religion — the rendering of due worship and obedience to God, and the attainment of salvation for oneself and others. Someone's religious practice is rational in so far as he or she has reason for believing that practising his or her religion is the best way to achieve these purposes, and that these purposes are greatly worthwhile.

Keywords: belief, God, rationality, religion, salvation, trust