I have a lot of books in my queue, but when Mitchell Stephens's Imagine There's No Heaven: How Atheism Helped Create the Modern World (Palgrave, 2014) came out, it went straight to the top. The book does not disappoint. I have not encountered a decent overview of the history of atheism since Thrower's Western Atheism: A Short History (Prometheus Books, 1999). Now, that particular torch has been passed to Stephens.
There is a personal note toward the end of the book that highlights how far at least Western civilization has come with respect to atheism just in the last fifty years, much less since the days of the auto-da-fé:
I first contemplated writing writing a history of atheism and its accomplishments a couple of decades ago. I was distracted then by other projects. But I must admit I considered at that time what the reaction to such a book might be. Should I fear protests? Would I be invited to promote the book on the air? Now, in the United States in the second decade of the twenty-first century, such fears seem quaint.
There is much yet to be done, but seeing how much already has been won for reason in the face of intolerance and even violent persecution, it is difficult not to be optimistic about the future.