MicroRNA research and development is the billion-dollar baby and most lucrative option for drug discovery in gene therapy industries worldwide. Personalized microRNA treatments are in many cases the only remedy for viral diseases that have no cure in conventional drugs and offer to bring us closer than ever to “personalized medicine.” They also counteract cancer and other infectious and neuro-diseases. Early diagnosis, prognosis, staging, and sub-classification of various cancers can easily be facilitated by microRNA-based biomarkers. MicroRNA surveys recent advances in RNA and RNA-protein components that highlight RNA delivery, its stability, and applications of RNA-based drugs for the modulation of gene/protein expression and gene editing. The book not only focuses on the modern medicines of microRNA-based early diagnostic and therapy development, but also works as a hidden treasure for drug discovery of multiple rare diseases worldwide. It offers indispensable learning materials for academic researchers, graduate, and medical students, and offers a powerful practical guide for RNA-Pharma and gene therapy industries.