The book “Mycology, Microbiology and Plant Pathology” is a text written for Under – Graduate students of Botany studying in different universities in Rajasthan and other parts of the country. Students of B.Sc. (Honours) in Botany, B.Sc. (Agricutlure) and M.Sc. in Botany can also use this book as primer to more elaborated texts. During last few decades, we have witnessed deluge of new information, especially in the field of molecular biology, forcing us to look at the life and functions of microbes with altogether different approach. The book therefore, presents the most modern view about the microbes as we know them today. Nevertheless, the conservative view point about microbes has been retained for the convenience of readers transitioning into new era of our understanding about evolutionary biology based on genomics. However, most recent developments in molecular taxonomy, evolution and systematic of microbes such as Fungi, Mycorrhizae, Plant Viruses, Mycoplasma, Spiroplasma and Phytoplasma have been described in great detail. A brief account of pathogenic microbes, such as Viroids, Prions and AIDS Virus has been provided. Colour photo-plates included in a chapter on Symptoms of Plant Diseases, adds value to our understanding about symptoms manifested by plant under attack of various phytopathgens. A Glossary of Technical Terms and English-Hindi Dictionary of Technical Terms provided in the book will prove highly useful for the students. The amalgamation of traditional knowledge with most modern understanding about the microbes presented in this book makes it unique and different from other similar books available in the market.