The application of fluorescence in drug discovery, high-throughout screenings in genomics and proteomics is and will be evidently successful. The increased use of fluorescence techniques is greatly enhanced by the improved instrumentation pioneered by inventive scientists and now made available commercially by several high-tech companies. Moreover, the design and development of many new molecular probes with higher selectivity for specific microenvironmental properties has stimulated many new researchers to employ fluorescence techniques for solving their problems. Probably the most significant breakthrough in fluorescence is its use in detection of single molecules and even of their real-time dynamics. Also, probing inside living cells has become a hot topic in the life sciences. This topic book reflects the updates of scientific progress presented by frontline researchers.