RNA is a chemical found in the nucleus and cytoplasm of cells. RNA plays an important role in protein synthesis and other chemical activities of the cell. The structure of RNA is similar to that of DNA, although RNA is single stranded whereas DNA has a characteristic "double helix". Genetic information is stored by DNA in the nucleus of cells, and RNA carries that information to other parts of the cell where it is converted into protein. Three types of RNA are; mRNA (messenger RNA, which contains the specific sequence of nucleotides necessary to dictate amino acid sequence in proteins), tRNA (transfer RNA, which serves as the "adapter" to position the appropriate amino acid next to a growing polypeptide chain during protein synthesis), and rRNA (ribosomal RNA, which is the RNA component of ribosomes). This book presents state-of-the-research from throughout the world.