This chapter attempts to show that the thermodynamic laws are by no means just restricted to the study of thermal effects in man-made artefacts and heat engines. The growing evidence is that, provided they are applied with suitable caution, these laws can also explain, elegantly and succinctly, complex systems in the natural world. It is self-evident that some aspects of thermodynamics must apply to living organisms because life clearly depends critically on cell temperature. For humans death occurs for temperatures transgressing the quite limited range of 32–42°C. But why should this be? The chapter shows that thermodynamics can provide the answer. In thermodynamic terms it seems that life is comprised of two fundamental mechanisms: one ‘order from order’ and the other ‘order from disorder’. The inference is that living things can reverse entropy, thus defying the second law of thermodynamics. By using thermodynamics principles to resolve these apparent dilemmas, we seek here to illustrate their explanatory power.