There has been much said about the authorship of this book. Some have attempted to undermine the book by claiming that it was all or mostly written by Varghese, with Flew in a confused state of mind. Flew himself denied this. It also becomes clear in the style of writing as an essay from Varghese is included in the Appendix. It is the inclusion of this poorly thought out and scientifically illiterate essay at the end that has resulted in this book getting 4 stars instead of 5. The crass nature of this appendix contrasts with the rest of the book greatly.
The main body of the text is a marvelously honest account of the thinking of a great mind. Detailed philosophy has been as accessible as I ever seen it. The arguments are fine and concise. Each chapter could be expanded into a book in itself, and could certainly be the basis for a debate.
However, be under no illusion: this is not a Christian book. While passing references are made to Christianity, and indeed the second appendix is a typical tour-de-force that we have come to expect from Tom Wright, Flew (at the time of his death) was a Deist, not a Christian. This book is very much focussed on ontology.
Given his earlier position in life as an atheist it is good to see the inclusion of many atheistic arguments contained in this book. These are not straw men, as you may find in many other anti-atheistic writings and present the unbeliever with ammo and the believer with food for thought. Likewise, the second half of the book reverses the roles.