Michel Onfray's "Atheist Manifesto" is the latest of many recent books about religion, atheism and secularism. This book is not a scientific study or an attempt to disprove the religions, but a philosophical polemic against religions (an "Atheological treatise" as the original French title would translate) and a call for a post-Christian secularism.
Onfray is an atheist but he doesn't seem to be attempting to convert anyone to atheism, and indeed, his writing style is not likely to convert believers. Instead, the book is a polemic reflection about the effects of religion and a call to reason, probably aimed mostly at fellow atheists.
An interesting chapter of the book is spent deconstructing the myth of Jesus and how Christianity came to be the world's biggest religion and how some of it's teachings (especially those of Paul) may have come to be.
Another large portion of the book explains why religion has been the monotheistic teachings have caused so much evil. It's all very true but not exactly news.
The real purpose of the book comes in the last few pages, where he returns to something he wrote about in the beginning of the book. Here he says the choice is not between western Judeo-Christian values and Muslim values, but between religion and secularism. According to Onfray, much of the current secular values have their roots in the Judeo-Christian tradition, and he calls for a post-Christian secularism with post-Christian ethics.
Onfray is obviously a very knowledgeable philosopher and he makes many good points. The book is probably aimed at atheists and philosophers. It's not a book to start with for those new to atheism or those with only a sporadic interest in ahteism or religion, but at the same time, for the already-convinced atheist, such as myself, there's really not much new to be found in this book.