Topics covered in this book include RNA silencing and its suppression in plant virus infection, virus replication mechanisms, the association of cellular membranes with virus replication and movement, plant genetic resistance to viruses, viral cell-to-cell spread, long distance movement in plants, virus induced ER stress, virus diversity and evolution, virus-vector interactions, cross protection, geminiviruses, negative strand RNA viruses, viroids, and the diagnosis of plant viral diseases using next generation sequencing. This book was anticipated to help plant pathologists, scholars, professors, teachers and advanced students in the field with a comprehensive state-of-the-art knowledge of the subject.