Entropy for Biologists: An Introduction to Thermodynamics provides an introduction to the fundamental concepts of thermodynamics for biologists. It begins with discussions of basic principles such as temperature, energy, kinetic theory, total energy, the second law of thermodynamics, and entropy. It then reviews conceptual tools from probability theory, combinatorial analysis, and information theory, which are essential to understanding elementary statistical mechanics. The remaining chapters present formulations for the relation between statistical mechanics and thermodynamics; the relationship between entropy and information; free-energy functions; and thermal energy. Measurements of temperature, energy, and thermochemical quantities are covered. The final chapter discusses the biological implications of the relation between entropy and information. This book is intended for graduate and advanced undergraduate students of biology and biochemistry who wish to develop a sense of confidence about their understanding of the thermal physics which will be useful in pursuing their work. It may also prove useful to professionals who wish to bolster their knowledge in this area.