Germfree Research: Biological Effect of Gnotobiotic Environments is an account of the Proceedings of the Fourth International Symposium on Germfree Research. The volume comprises of 12 sections and 97 chapters. The first two sections serve as introduction to the status of germfree research as an approach to micro-ecology and gnotobiotic technology in clinical medicine. Another aspect discussed in the book deals with nutrition, metabolism, and microbiology. The last section provides a thorough and detailed discussion on gnotobiotic technology. Large part of the book focuses on gnotobiotic environments and its different aspects. Topics discussed include gnotobiotic environment on isolated patients and in dentistry and parasitology, as well as carcinogenesis in and physiological effects of gnotobiotic environments. The book is a very valuable source of information for many students and professionals in the fields of clinical medicine, biology, microbiology, nutritional science, and biochemistry.