This book provides an overview of viral genomes. It is an all-inclusive book on the vast subject of viral genomes. Viruses are small agents which cause infection within the host by multiplying inside the functioning cells of the host. The comprehension of the molecular incidents underlying the infectious procedure has been of particular significance to advance strategies intended to combat viral disorders of medicinal, veterinary and agricultural significance. Few viruses cause horrible diseases, while others are also of interest due to various reasons. The writers of this book present the readers with a viewpoint on the broad range of virus-host systems. This book deals with a wide variety of topics such as genome diversity and development, virus-host interactions, counting technically significant features, regulation of replication and gene expression. This book also covers a huge range of scientific approaches to assess genome deviation or stability. It intends to provide useful data regarding many features related to viral genomes for both students and experts.