“What may be known of God is manifest,” wrote Paul in his letter to the Romans. In other words, the evidence is plain. However, Christians can get lost. They wrestle with doubt, and they can be overcome by the fear that what they believe is foolish. Author Peter Zelinski knows this doubt and fear well; he faces it himself. In “How Do We Know God Is Real?”, Zelinski provides a trail out of this dark wood. He offers the argument based in reason by which the believer can return to knowing that God certainly exists. “Our faith in him is built on a more substantial foundation than just our fragile hope,” Zelinski writes. As Paul’s line to the Romans suggests, we can infer the reality of God from our experience of the world. In fact, we don’t have to look far. Zelinski reveals that our very experience of self provides the case for God’s reality. His short book is a letter of reassurance to every Christian who struggles with doubt, which might mean that it is written to every Christian.