Abstract
Broadly speaking, thermodynamics is the study of the relation of heat and other forms of energy (mechanical, electrical, radiant, etc), and the conversion of one form to another, as well as their relation to matter in the Universe. This chapter gives an overview of the major concepts, laws, and branches of thermodynamics that have been developed and studied over the years since the Carnot times. Specifically, this chapter defines the basic physical concepts of thermodynamics, with emphasis on the fundamental concept of entropy, and presents the four laws of thermodynamics. Particular aspects studied are the entropy interpretations (unavailable energy, disorder, energy dispersal, opposite to potential), the Maxwell demon, and the types of arrow of time (psychological, thermodynamic, cosmological, quantum, electromagnetic, causal, and helical arrows). This chapter ends with a number of seminal quotes on thermodynamics, entropy, and life that express the opinions of the founders and other eminent contributors and thinkers in the thermodynamics field.