The interaction of light with matter forms the foundation of both fundamental physics and modern photonic technologies. This course explores light-matter interactions across subwavelength to quantum regimes, developing a coherent framework for controlling light at the nanoscale. Students in this course will develop a comprehensive understanding of nanophotonics and metamaterials through theoretical modeling, computational simulations, and experimental methodologies. Key topics include the introduction of hybrid light-matter states, fabrication techniques for nano/metaphotonic structures, and the integration of these concepts into practical devices, such as- sensors, detectors, and integrated photonic systems. The course concludes with inverse-design principles for advanced nano- and metaphotonic systems and an introduction to quantum nanophotonics, including single-photon sources and detectors.