The article by Stefan W. Hell and colleagues reviews the advancements in far-field optical nanoscopy, which has pushed the resolution limits of conventional fluorescence microscopy beyond the diffraction barrier. The traditional limit of resolving details smaller than half the wavelength of light was overcome by exploiting the molecular states of fluorescent markers, allowing for subdiffraction-resolution imaging. Key techniques include stimulated emission depletion (STED) microscopy, ground state depletion (GSD) microscopy, and photoactivatable localization microscopy (PALM) and stochastic optical reconstruction microscopy (STORM). These methods enable the sequential readout of fluorescent markers within a diffraction-limited spot, allowing for the imaging of densely packed and similarly labeled features. The review highlights the potential of these techniques in various biological applications, such as visualizing protein clusters and organelles in live cells, and discusses the future prospects for improving imaging speed and efficiency.The article by Stefan W. Hell and colleagues reviews the advancements in far-field optical nanoscopy, which has pushed the resolution limits of conventional fluorescence microscopy beyond the diffraction barrier. The traditional limit of resolving details smaller than half the wavelength of light was overcome by exploiting the molecular states of fluorescent markers, allowing for subdiffraction-resolution imaging. Key techniques include stimulated emission depletion (STED) microscopy, ground state depletion (GSD) microscopy, and photoactivatable localization microscopy (PALM) and stochastic optical reconstruction microscopy (STORM). These methods enable the sequential readout of fluorescent markers within a diffraction-limited spot, allowing for the imaging of densely packed and similarly labeled features. The review highlights the potential of these techniques in various biological applications, such as visualizing protein clusters and organelles in live cells, and discusses the future prospects for improving imaging speed and efficiency.