Welcome to this Textbook of virology, this book offers insights into the nature of viruses, their biology, and their impact on human health. We start with an overview of virology, covering the general characteristics, discovery, morphology and taxonomy of viruses. Subsequent chapters focus on virus cultivation techniques used in laboratories, emphasizing both DNA and RNA viruses, their structures, pathogenesis, laboratory diagnosis and treatment of disease caused by these viruses. Additionally, we discuss antiviral agents, detailing how these medications function and their importance in treating viral infections. Each chapter is designed to provide a solid foundation in virology, and to be useful to undergraduate and postgraduate microbiology students, researchers, and healthcare professionals concerned with the significance of viruses in public health.