For Christians a useful place to start when thinking about the relationship of other religious traditions to Christianity is Joseph Ratzinger’s book Truth and Tolerance: Christian Belief and World Religions (San Francisco: Ignatius Press 2003). Written by the man who is now Pope Benedict XVI, this book is remarkably well researched and very readable. Interestingly he pays a fair amount of attention to the views of evangelical Christians with whom he agrees. The basic theme of the book is that Christian truth must be separated from the way Christians interact and live alongside people who belong to other religious traditions.
Rejecting mushy forms of dialog the then Cardinal Ratzinger argues that truth and tolerance are not incompatible. In his view it is possible to be a believing Christian who is thoroughly orthodox while at the same time respecting the beliefs of members of other faiths. Drawing on scripture and the Christian tradition this book presents an intelligent approach to religious pluralism which all Christians who affirm the historic creeds will find very helpful.
It is a good place for believing Christians to begin the study of religion.