I first came across this book when I read an extract from it in Francis Collins' anthology, Belief.
The book falls into two parts. The first is a rebuttal to various arguments put against Christianity, in an almost FAQ style format. The second half then puts forward a more positive case, giving reasons and evidence for why Christianity is true. This appealed to me a lot, as most apologetic writing I have read tends to deal with one of these whilst not stating the other side particularly well. (For the former, see the writings of Alister McGrath; for the latter, see Tom Wright).
The style of arguments will be very familiar to those who have read C.S. Lewis' Mere Christianity, and indeed Lewis is quoted frequently and properly credited at the end as being a significant source of inspiration for this book. So really, what it boils down to, is a 21st century update of that former apologetic work. This is not the only author from whom much has been borrowed. The chapter on the resurrection reads very much like a summary of N.T. Wright's The Resurrection of Son of God.
Now Tim Keller comes across in the book as an immensely likeable chap; he is very warm and rarely patronising. In fact the one verse that came to my mind was 1 Peter 3:15 “Always be prepared to give a reason for the hope that you have; but do this with gentleness and respect.” This book is an outliving of that motif, which is one that I hold dear to my heart and always have in mind whenever I am questioned (by others or myself) on my faith.
There are hints in this book, which is more evident in other things he writes, that Keller is no fool. The footnotes give a hint to the depth and breadth of his study, and frequent reference is made to his own real-life experiences of leading a church in New York. But this mighty intellect is a little restrained here, in order to make the writing more accessible to a lay audience, and not be over-cerebral. This at once gives the book its greatest strength and one of its key weaknesses. The strength is that is highly accessible, and there is no complicated theological discussion or over-philosophising at the risk of losing sight of the goal. This does then have the drawback that it is not a watertight case. To most of the arguments presented there could always be at least one counter-argument. However, Keller has not had the time or space to cover all comebacks and possible disagreements.
The best chapters are those on the resurrection (mentioned above), justice and suffering. Where I personally disagree with him was on page 142 (and the subsequent chapter) where he attempts to show that people already know God exists. If this were the true, then it would not be such a bone of contention as it has been throughout human history.
It is very close to being a great book but the incompleteness of the arguments prevent of being such; nonetheless, it is still one of the better books out there in the field of modern christian apologetics and I would recommend it to anyone who is interested in, and open-minded about, christianity, or has recently done something like an Alpha course, or Christianity Explored; though I doubt it will convince those who are determined not to believe.