Engaging the two central objections identified by St. Thomas Aquinas, the problem of evil and the alleged sufficiency of the natural world, this rigorous yet accessible work presents a powerful defense of classical theism. Drawing from Aristotle, Aquinas, Leibniz, and other great thinkers, it explains key philosophical principles and offers clear cosmological arguments, insights from consciousness and morality, and a careful treatment of fine tuning and scientism. With precise definitions and thoughtful replies to common challenges, this book equips readers to understand the intellectual foundations of belief in God and to respond confidently to the claims of atheistic naturalism.