Small non coding RNAs (ncRNAs), also known as the secret regulators of the cells, have been discovered only 20 years ago, and it has been much more recently that the attention of the scientific community has been turned towards the structure and function of ncRNAs in plants. Indeed, it has been found that the higher the organisms have been developed, the larger the numbers of ncRNA genes encoded in their DNAs. With this book the editors have been able to solicit the best ncRNA plant researchers in the world to report on their most recent discoveries concerning the importance of small ncRNA in plants. The book is a “must” for those, who are interested in the molecular regulation processes involving ncRNAs in plants.