There are many books which set out the case for Islam or for Christianity and point out what they regard as defects in the other religion. This book does that, but it seeks to do so in the form of a workbook which groups of Christians or Muslims might use, and it is conducted in a spirit where truth is paramount but so too is kindness and civility. The two authors have become friends and hope that this can be detected in the exchanges. As the major doctrines of each religion are dealt with, we are conscious that these doctrines are important and need to be examined rigorously and charitably. We hope we have succeeded to some degree at least.