The article discusses advancements in far-field optical nanoscopy, which has enabled subdiffraction resolution in fluorescence microscopy. It highlights the physical principles behind breaking the diffraction barrier, such as using molecular states for signal generation and overcoming diffraction limits. Key concepts include stimulated emission depletion (STED), ground state depletion (GSD), and RESOLFT, which use bright and dark states of fluorescent markers to achieve subdiffraction resolution. The article also covers other techniques like PALM and STORM, which rely on stochastic switching of fluorophores to image at the nanoscale. These methods have significant implications for life sciences and other fields requiring nanoscale visualization. The text references numerous studies and provides links to related articles, supporting materials, and citations. It emphasizes the importance of computational methods and the potential of these techniques to enhance imaging resolution beyond traditional electron and scanning probe microscopy. The review underscores the progress in overcoming the diffraction limit and the future potential of far-field optical nanoscopy in various scientific applications.The article discusses advancements in far-field optical nanoscopy, which has enabled subdiffraction resolution in fluorescence microscopy. It highlights the physical principles behind breaking the diffraction barrier, such as using molecular states for signal generation and overcoming diffraction limits. Key concepts include stimulated emission depletion (STED), ground state depletion (GSD), and RESOLFT, which use bright and dark states of fluorescent markers to achieve subdiffraction resolution. The article also covers other techniques like PALM and STORM, which rely on stochastic switching of fluorophores to image at the nanoscale. These methods have significant implications for life sciences and other fields requiring nanoscale visualization. The text references numerous studies and provides links to related articles, supporting materials, and citations. It emphasizes the importance of computational methods and the potential of these techniques to enhance imaging resolution beyond traditional electron and scanning probe microscopy. The review underscores the progress in overcoming the diffraction limit and the future potential of far-field optical nanoscopy in various scientific applications.