Germfree Life and Gnotobiology focuses on the theory and general aspects of germfree research and gnotobiology. Using a phylogenetic approach, the book provides a summary of germfree work in all phyla, from bacteria and viruses to protozoans and invertebrates. It characterizes germfree vertebrates based on data on morphology, biochemistry, nutrition, serology, and physiology. This book is organized into six chapters and begins with an overview of germfree life and gnotobiology, including biological isolation as the basis of germfree life, germfree conditions in nature, and the biological significance of germfree research. A section is devoted to nomenclature and terminology. The chapters on methods and nutrition are sufficiently detailed to serve as guides for experimental work. The book concludes with a chapter on exploratory research that explores the inoculation of germfree animals with known kinds of microorganisms. Terms have been introduced to describe concepts and provide precise communication. This book is a valuable source of information for scientists and researchers engaged in germfree research as a biological tool.