The article reviews the development and application of optogenetic tools in neuroscience. Optogenetics, which uses genetically encoded light-sensitive proteins to control specific cells within complex neural tissues, has revolutionized neuroscience by enabling precise and specific modulation of neuronal activity. The review highlights the evolution of optogenetic tools, particularly microbial opsins, and their diverse applications in various model organisms. Key advancements include the discovery and improvement of channelrhodopsins (ChR1 and ChR2) and halorhodopsin (NpHR) for neuronal excitation and inhibition, respectively. These tools have been used to study a wide range of neural functions, from muscle control in *C. elegans* to complex behaviors in mice. The article also discusses methods for delivering optogenetic tools into neuronal systems, including viral expression systems and transgenic animals, and the challenges and opportunities in targeting specific neuronal populations. Additionally, it explores the integration of optogenetics with other techniques such as electrophysiology and imaging to enhance the understanding of neural circuits and their roles in behavior and disease.The article reviews the development and application of optogenetic tools in neuroscience. Optogenetics, which uses genetically encoded light-sensitive proteins to control specific cells within complex neural tissues, has revolutionized neuroscience by enabling precise and specific modulation of neuronal activity. The review highlights the evolution of optogenetic tools, particularly microbial opsins, and their diverse applications in various model organisms. Key advancements include the discovery and improvement of channelrhodopsins (ChR1 and ChR2) and halorhodopsin (NpHR) for neuronal excitation and inhibition, respectively. These tools have been used to study a wide range of neural functions, from muscle control in *C. elegans* to complex behaviors in mice. The article also discusses methods for delivering optogenetic tools into neuronal systems, including viral expression systems and transgenic animals, and the challenges and opportunities in targeting specific neuronal populations. Additionally, it explores the integration of optogenetics with other techniques such as electrophysiology and imaging to enhance the understanding of neural circuits and their roles in behavior and disease.