This book is designed for use in an introductory course in thermodynamics. It is aimed at students of Physics, Chemistry, Materials Science, and Engineering. As an undergraduate text, it gives a clear description of the theoretical framework of thermodynamics, while providing specific examples of its use in a wide variety of problems. These examples include topics that are atypical of undergraduate texts, such as biological systems, atmospheric phenomena, and polymers. The narrative is infused with historical notes on the characters who make up the story of thermodynamics, enlivening the material while keeping the reader engaged.