Publisher Summary This chapter discusses fire and describes the interaction of bodies and fire and offers some guidelines for processing fire-damaged remains. Fire is an exothermic oxidation reaction between a fuel and an oxidizer (most often the oxygen in the surrounding air) that generates sufficient heat to be self-sustaining and yields readily detectable heat and often light. Fire requires four basic ingredients—fuel in a suitable form, oxygen, heat, and a chemical oxidation that causes the reaction to be self-sustaining. Without all four, there cannot be a fire. Fire occurs in two basic forms—flaming and smoldering. When assessing fire damage to human remains, the relationship between the remains and the fire is critical. The physical and thermal relationships and conditions are not static through a fire. No two fires are exactly alike. Temperatures can vary enormously, heat fluxes change often and rapidly, and ventilation conditions change continuously and sometimes dramatically. Bone is a complex composite material that can vary even with its basic starting conditions.