Book excerpt: RNA technologies are the driving forces of modern medicine and biotechnology. They combine the fields of biochemistry, chemistry, molecular biology, cell biology, physics, nanotechnology and bioinformatics. The combination of these topics is set to revolutionize the medicine of tomorrow. After more than 15 years of extensive research in the field of RNA technologies, the first therapeutics are ready to reach the first patients. Thus we are witnessing the birth of a very exciting time in the development of molecular medicine, which will be based on the methods of RNA technologies. This volume is the first of a series. It covers various aspects of RNA interference and microRNAs, although antisense RNA applications, hammerhead ribozyme structure and function as well as non-coding RNAs are also discussed. The authors are internationally highly respected experts in the field of RNA technologies.