In my opinion, this book provides a good introduction to atheism and related philosophical issues. The hostile-sounding title might put some people off, but Smith makes it clear in the first section of his book that the primary focus of the book is whether or not theistic claims should be accepted as true. If one can show that theistic belief if flawed (the case against god), then one supports atheism.
Smith then proceeds to do just that for the remainder of his book. He covers basic and important subjects such as god concepts, faith, morality, and common arguments for god. Smith argues that no rational person can accept theism as true and he discusses the philosophical problems of many theistic arguments. Smith writes in a non-technical style, and this may be why the book is popular. I think Smith's book could serve as a good starting point for approaching more thorough and technical books on atheism.
Smith spends much of the book analyzing Christianity, and I would have preferred it if he spent more time looking at theism in general. Throughout the book, he describes major flaws in Christianity, and after awhile it appears as though he's just whipping a dead horse. Of course, it's a dead horse that many people insist on riding, so I suppose that critiquing it from several perspectives may help to convince some of the riders that they're not going anywhere on that beast.
If you are a philosophical layperson who wants to learn more about atheism, then this is the book you should read.
Now, if I may digress, it appears that some of the reviews posted before mine do not really review the book at all. Instead, they provide theistic arguments that supposedly refute the arguments that Smith makes in his book. It is interesting to note that the theistic arguments offered below are actually covered in Smith's book, where he shows them to be flawed. It makes me wonder if some of those reviewers actually read or understood the book.