microRNA (miRNA), like a language, is full of regulators for our lives. Function of miRNAs is simple to tell – for instance, post-transcriptional suppression; however, its mechanisms are more tricky and explanation of miRNAs’ role in evolution causes difficulty even graduated students and top researchers. How exactly is the information of miRNA used? What is the difference between CeRNA theory and RNA wave 2000? What are the real rules for disease induction and cure? When do we use the expression of miRNAs? How do you say, miRNA is information and not epigene? Where does miRNA locate? When are miRNAs transmitted? And so on, and so on. This book would be a practical reference guide to problems of these kinds. But there is no point that is lie or truth. Therefore, the book is intend for not only intermediate and advanced scientists or students but also scientific enthusiasts. Being references, it contains information at various journals, ranging from review articles to very unique articles. Finally readers would decide lie or truth, or near pin or not because research of concept in miRNAs is in progress day by day by over 10,000 references per year on 2016.