Antibiotics: Origin, Nature and Properties, Volume I is a systematic coverage of the sources, varieties, and properties of the antibiotics. This book is organized into two main parts encompassing 13 chapters. This book considers the antibiotics according to their sources. It describes the antibiotics produced by bacteria, Actinomycetes,Fungi imperfecti, Basidiomycetes, algae, lichens and green plants, and those from animal sources. This group of antibiotics includes, streptomycin, the tetracyclines, chloromycetin, the macrolide family of compounds of which erythromycin, magnamycin and spiramycin are members, and the antifungal polyene compounds. The members of each group are arranged according to their chemical and biological similarity. Sections on each antibiotic present complete information, including the name, description of the producing strains, composition of the media, methods of culture, isolation and purification of the antibiotic principle, its physical and chemical properties, antibiotic spectrum, toxicity for laboratory animals, results of treatment of experimental infections, and possible clinical applications. This book is of value to researchers and workers in various medical fields.