The church in the West is at a critical moment. While the gospel is exploding throughout the global south, Western civilization faces militant assaults from aggressive secularism and radical Islam. Will the church resist the seductive shaping power of advanced modernity? More than ever, Christians must resist the negative cultural forces of our day with fortitude and winsomeness. What is needed is followers of Christ who are willing to face reality without flinching and respond with a faithfulness that is unwavering. Os Guinness describes these Christians as impossible people, those who have hearts that can melt with compassion, but with faces like flint and backbones of steel who are unmanipulable, unbribable, undeterrable and unclubbable, without ever losing the gentleness, the mercy, the grace and the compassion of our Lord. Few accounts of the challenge of today are more realistic, and few calls to Christian courage are more timely, resoluteand hopeful. Guinness argues that we must engage secularism and atheism in new ways, confronting competing ideas with discernment and fresh articulation of the faith. Christians are called to be impossible people, full of courage and mercy in challenging times.