The God Delusion, by Richard Dawkins, is aptly named. It illustrates how the concept of a personal god (specifically the Abrahamic god of Judaism, Christianity, and Islam) is one of complete fiction, and yet has so many convinced of His existence, despite the mounting evidence that the world is not as described in ancient scripture.
Dawkins’s approach to his arguments against theistic belief in the supernatural is an obvious extension from his career in evolutionary biology. Dawkins is very careful to take the time to define each term that he uses, sorting out the different meanings, so that his specific use of the term is clearly understood. This goes a long way to avoid confusion, especially when talking about the polytheistic, monotheistic, pantheistic, and panentheistic uses of the word ‘god’. Dawkins is also very good at presenting a much more complete picture of commonly misrepresented & quote mined historical figures such as Einstein, the American founding fathers, Hitler, etc., and shows how their uses of the word ‘god’ rarely meets today’s Christian definition.
Dawkins’s ‘The God Delusion’ is a scientific approach, in methodology if not evidentiality, to the arguments against the beliefs in gods, and is much more reserved and soft-spoken than Christopher Hitchen’s rather abrasive book, ‘God is Not Great: How Religion Poisons Everything’. These two books have a stark contrast in their delivery, but share the same sound reasoning and logic. I highly recommend both of them.