Most of the scholarly literature on sin has focused on theological issues, making book-length philosophical treatments of the topic hard to find. "Sin," the newest contribution by Gregory Mellema, fills the gap by providing a short and lively summary of what contemporary philosophers are saying about the relationship between the traditional theological category of sin and contemporary philosophical ethics. Mellema brings together contributions by a number of philosophers, including Marilyn Adams, Robert Adams, Rebecca DeYoung, Alvin Plantinga, Michael Rea, Eleonore Stump, and Richard Swinburne, into a coherent discussion that clarifies our understanding of the nature of sin.