Richard Dawkins, a supporter of atheism, as well as the author of the well-known book The God Delusion

Atheism is rejecting the belief in a God or gods.It is the opposite of theism, which is the belief that at least one god exists. A person who rejects belief in gods is called an atheist. Adding an a, meaning "without", before the word theism results in atheism, or literally, "without theism".