If non-Christians are totally depraved, and if depravity is the corruption of all areas of life, then how can believers and nonbelievers cooperate on anything? Worse, how can they communicate? Indeed, how is it possible for nonbelievers to say anything true? This is a major area of discussion in Reformed theology. Calvin wrestled with it, and Abraham Kuyper devoted three volumes to it. In the early 20th century there was a controversy in the Christian Reformed Church on the subject. Van Til was drawn into the discussion because he had friends on both sides, and because his apologetic places into the center of discussion the non-Christian's suppression of the truth (Rom. 1). Van Til's account of the matter has been controversial, even among his disciples. But there is much we can learn from him on this subject, and anyone who wants to understand his apologetic and theology must engage his thought at this point. Scott Oliphint, who has edited other works of Van Til, has taken up the difficult but worthy task of explaining Van Til˙s thoughts on common grace to twenty-first century readers.