"Salt of the Earth" by P. Rajan Mathews is a Christian devotional book that uses the metaphor of salt to explore principles of Christian living. Drawing from Jesus' declaration "You are the salt of the earth" (Matthew 5:13), the author examines salt's physical and chemical properties as spiritual parallels. The book covers twelve dimensions of "salt living," including being chosen, crystalline (pure), hardworking, cooperative, humble, and patient. Mathews, a food industry executive with an agricultural sciences background, connects biblical wisdom with modern insights from leadership, nutrition science, and psychology. Each chapter explores how salt's characteristics—preservation, flavor enhancement, and transformative power—mirror the Christian's role in society. The work emphasizes that Christians should function like salt: essential but often unnoticed, enhancing their environment without overpowering it, and maintaining their distinctive character while engaging with the world. The author argues that ancient biblical principles remain relevant for contemporary challenges in leadership, relationships, work, and community engagement. The book concludes with a call to actively live out these salt-like qualities rather than merely understanding them intellectually.