The phenomenon of fluorescence has revolutionized research in biology and medicine. More than 100 years ago, Paul Ehrlich began to develop specific chemical staining methods and the latest development of light-controlled proteins (optogenetics) will surely not mark the end of this progression. A historically continuous trend is the quest for measuring and quantifying data, with or without generation of images as data source. Many techniques have been introduced that are based on fluorescence, but not necessarily require image formation. The laboratory jargon refers to this methods as “F-techniques”: FLIM, FCS, FCCS, FRET, FRAP… to mention just the most important. Read the articles in this topic, to find out more details on these modern methods.