Greg Gilbert's book What is the Gospel? explores the profound meaning of the Christian message of the Gospel, viewing it not only as a message of salvation, but also as a central teaching about God's holiness, human sin, the sacrifice of Jesus Christ, and the restoration of the world through Him. The author emphasizes the importance of correctly understanding and preaching the Gospel, analyzing cultural influences that can distort its true meaning, and calls for a deeper understanding of how the Gospel should be communicated in the modern world.