As some of the simplest organisms, bacteria have a close connection to physics and chemistry. This book investigates how these organisms solve their problems. They do so in a way that is adequate but less dependent on the evolution of very sophisticated biological tools that are so prominent in the biology of eukaryotic plants and animals. This simplicity is a consequence of the fact that the domain of bacteria separated from the evolutionary tree earlier than the other two domains. Early parts of the book are devoted to evolutionary processes and mathematics for the study of bacteria growth. Also presented are the physics of osmotic pressure, surface tension, and relevant aspects of biochemistry.