The mixing of the qualities of hot, cold, wet, and dry create the four elements of earth, air, fire, and water for ancient Greek philosophy and ecoculture. The elements themselves should not mix, such as earth and water mixing to make wetlands. The mixing of the elements of air and water also gave rise to malaria, both literally bad air and a disease. The element of water gave rise to monsters; most monsters are water-beings, or mix water with one or other of the elements. The elements also gave rise to humors, or psychological states, even psychosomatic affects. The mixing of the qualities of cold and dry gave rise to the element of the earth, and in turn to the humor of melancholy, one of the persistent maladies of modern western culture in its transformations into sloughs of despondency and mires of depression. Melancholy is associated with mourning and death, so detective stories have been particularly fascinated with it. This chapter traces the genealogy of the elements and the humors, especially melancholy, and the monstrous in western philosophy, culture and medicine from AristotleAristotle, PlatoPlato, HippocratesHippocrates, and HerculesHercules through seventeenth-century philosophy and theology and nineteenth-century detective fiction to twentieth-century cultural studies.