This book provides up-to-date information on the molecular diagnosis of viral diseases, including COVID–19, zika virus, human immunodeficiency virus (HIV), viral hepatitis, meningitis, and human papilloma virus (HPV). It covers global trends, the impact of viruses on society, and the need for molecular diagnostics. Initial chapters include information on popular molecular diagnostic methods and up-to-date strategies like Nucleic Acid Testing (NAT) and immunological methods, with an understanding of the challenges in their development. Further chapters emphasize emerging and next-generation diagnostic tools such as Specific High-sensitivity Enzymatic Reporter un-LOCKing (SHERLOCK), DNA Endonuclease Targeted CRISPR Trans Reporter (DETECTR), and Heating Unextracted Diagnostic Samples to Obliterate Nuclease (HUDSON), which boast a sensitivity of up to attomolar. The book also discusses high-end platforms like QIAsymphony. It is supplemented with illustrations and figures to aid conceptual understanding. The book is relevant for researchers in virology, clinicians involved in the therapy of viral diseases, and professionals in pathology labs interested in learning about advanced molecular diagnostic approaches for viral diseases.