This book reviews the structure-function relationship of nucleic acids, their role in the pathophysiology of the diseases, and as therapeutic targets for human diseases. The chapters discuss the role of nucleic acids in inflammatory diseases, neurodegenerative diseases, and cancer. The book also describes recent advancements in nucleic acid-based therapy, the application of nucleic acids in diagnostics, in the development of nano-carriers, logic gates, and sensors. It explores the use of nucleic acids (RNA and DNA) as a unique and multifunctional platform for numerous applications, including therapeutics, diagnostics, nanodevices, and materials. It further examines the role of DNA methylation, histone modifiers and readers, chromatin remodelers, microRNAs, and other components of chromatin in the progression of cancer. The book also discusses the applications of nucleic acid as a vaccine and as a gene-editing tool. It also provides an overview of the clinical trials using genome editing platforms for disease treatment and the challenges in implementing the editing technology. Finally, the book elucidates a representative description of challenges associated with nucleic acid-mediated therapy.