This book describes the methods of collection of microorganisms from soil, pure culture of the microorganisms and isolation of a highly antagonistic microorganism from various types of organisms. It also describes the determination of the optimum conditions for maximum growth of the specific microorganism as well as the best yield of the secondary metabolites. The procedures of isolation of antimicrobial compounds from the crude extract, determination of antimicrobial activities, cytotoxic effect and sub-acute toxicity study of the isolated compounds have been described in the book.