MicroRNAs (miRNAs) are a class of non-coding RNAs found in plants, animals and some viruses. They play a significant role in the regulation of gene expressions and are involved in all physiological processes. These physiological processes include development and differentiation, heart function, metabolism, hemostasis, and apoptosis. The alteration of the miRNA function is associated with some diseases and disorders such as cancer, inherited diseases, cardiovascular diseases and neurodegenerative diseases. Most of the miRNAs are transcribed from DNA sequences to produce primary miRNAs, which are then processed into precursor miRNAs. These finally turn into mature miRNAs. This book provides comprehensive insights into the regulation and clinical applications of microRNA. A number of latest researches have been included to keep the readers up-to-date with the global concepts in this area of study. With state-of-the-art inputs by acclaimed experts of this field, this book targets students and professionals.