Graham Oppy is Professor of Philosophy and Associate Dean of Research at Monash University, CEO of the Australasian Association of Philosophy, Chief Editor of the Australasian Philosophical Review, Associate Editor of the Australasian Journal of Philosophy, and serves on the editorial boards of Philo, Philosopher's Compass, Religious Studies, and Sophia.
He is one of the best known atheist thinkers in academia. You can buy "Atheism: the Basics" here.