The book is an outcome of the increasing awareness that microbes are the basis of the biosphere. The New Education Policy of University of Delhi, offers Industrial and Environmental Microbiology as a Discipline Specific Elective - (DSE) paper. The main focus of this paper is to appraise students with concepts, principles, scope and application of industrial and environmental microbiology, besides the career options this field has to offer. Likewise, the University of Delhi offers at least two papers - Biofertilizers, and Organic Farming for Sustainable Development as the Skill Enhancement Courses - (SEC). The objective of Biofertilizer paper is to enable students gain knowledge on eco-friendly fertilizers like Rhizobium, Azospirilium, Azotobactor, cyanobacteria and mycorrhizae, their identification, growth multiplication, biocontrol of diseases and recycling of the organic waste. On similar lines Organic Farming for Sustainable Development deals with \'Jaivik Kheti\' for sustainable growth. Aimed to cater undergraduates studying the applied aspects of biotechnology and microbiology courses, and the students of food science and biochemical engineering, this book provides wide-ranging applications of microbes. For teachers it is designed to cover the scope and requirements for the core and elective papers. The textbook reinforces key concepts and is therefore a must-have literature on the bookshelf.'