Human thermodynamics is the study of the energy and entropy aspects of the work cycles involved in human life, namely those existent between heat, spontaneity, irreversibility and the laws defining therein. In short, human thermodynamics is the study of heat and its relation to the motion and changes in the equilibriums of human bodies. The essential process of thermodynamics is that whereby heat cycles through a system of chemical species, e.g. water molecules in a steam engine or human molecules in a social system (sociological thermodynamics) and thereby mediates the production of work. In simple terms, heat, in the form of gamma-ray photons, cycles from the sun, the systems are coupled economies, the chemical species are people, and the work is the work of life. The four laws of thermodynamics define the boundaries of this action.