Fundamentals of GATE Microbiology is intended for GATE Life Sciences aspirants and UPSC-IFSC, IBPS, Forest Officer, UGC-NET, ICAR-ARS, ICAR-NET, CSIR-NET, JRF, SRF, IARI Ph.D., BHU, and Graduates. This book is important because of its broad concepts and explanations related to microbiology as per the GATE syllabus. This book contains eleven sections, each of which contains different concepts of microbiology. This review importantly highlights the history, scope, and development of microbiology and classification of microorganisms; microbial growth in the ecosystem in different conditions, microbial pathogens and immunity systems; different microbiological techniques, and microbial interactions, soil, water, air, and sewage microbiology. The new components which have required a change in worldview in microbiology with modern microbial science and biotechnology have been shown. However, the book is fully GATE syllabus oriented and written by considering their understanding abilities for competitive exams and graduate studies.