Is there a God? What is God?
Do you believe in God? Which God? If you think there is a God what is this god like. What can god do? What has God done?
These are all good questions and the answers can be complicated. Or you may think the answers are simple. Richard Dawkins is both a highly respected scientist and a leading thinker and writer about the roles of god and religion in the rational life.
If you do not believe in God or are questioning your belief in God this may be just the book you need to clarify your thinking.
Given the heavy subject matter (God and gods, beliefs, morality, and science), it was a surprising pleasant and relatively quick read. I found the book very easy to read and a clear explanation of why he does not believed in god.
His previous book, The God Delusion, is a somewhat similar explanation but much more detailed and as a consequence a harder and longer read. I would suggest starting with Outgrowing God and moving on to The God Delusion if you found the first book useful or interesting.
In addition his books, the Richard Dawkins Foundation for Science & Reason (https://www.richarddawkins.net/) is an excellent resource for those with interests in scientific literacy, secularism, religion (or lack of religion).