It gives great pleasure and satisfaction to fulfill the long felt need of microbiologists and students for a comprehensive on fundamentals of microbiology. Experience gained from teaching agricultural microbiology encouragement gained from the university, faculty members and Library facilities have made the dream come true. The modern phylogenetic classification and driscription of fungi, bacteria, virus and viroids have been present in a readable form so that it will be student friendly. This book will definitely pave the way for the young aspiring microbiologist mind to take up the subject with confidence.