These lecture materials explore the diverse and vital roles viruses and microorganisms play in both living systems and industrial processes. They start by tracing the intricate life cycles of bacteriophages and animal viruses, revealing how some pathogens can trigger tumor growth or cause neurological harm through prions. Shifting the focus to industry, the content showcases microbes as indispensable agents in water purification and the production of a variety of products, including pharmaceuticals, enzymes, and food additives. Emphasizing health and safety, the lectures delve into food preservation methods like pasteurization and highlight the enduring benefits of probiotics and prebiotics. The presentation concludes by underscoring the crucial role of bioremediation, where targ ...