Cavity optomechanics explores the interaction between electromagnetic radiation and mechanical motion. This review covers optical cavities, mechanical resonators, their optomechanical coupling via radiation pressure, experimental systems, optical measurements of mechanical motion, cooling, nonlinear dynamics, multimode optomechanics, and future perspectives. It discusses fundamental quantum physics and potential applications of optomechanical devices. Optical cavities store and manipulate light, while mechanical resonators oscillate. The optomechanical coupling arises from radiation pressure forces, which mediate the interaction between light and mechanical motion. Experimental systems include suspended mirrors, optical microresonators, waveguides, and nano-objects. Optical measurements of mechanical motion involve quantum noise and feedback cooling. Nonlinear dynamics and multimode optomechanics are also discussed, along with quantum protocols and hybrid systems. The review highlights the role of radiation pressure in cooling and the quantum fluctuations that limit measurement precision. It discusses the standard quantum limit, quantum non-demolition measurements, and optomechanical cooling. The field has advanced rapidly, with applications in quantum information processing, precision measurements, and fundamental tests of quantum mechanics. Future directions include improving quantum coherence and exploring new systems for optomechanics.Cavity optomechanics explores the interaction between electromagnetic radiation and mechanical motion. This review covers optical cavities, mechanical resonators, their optomechanical coupling via radiation pressure, experimental systems, optical measurements of mechanical motion, cooling, nonlinear dynamics, multimode optomechanics, and future perspectives. It discusses fundamental quantum physics and potential applications of optomechanical devices. Optical cavities store and manipulate light, while mechanical resonators oscillate. The optomechanical coupling arises from radiation pressure forces, which mediate the interaction between light and mechanical motion. Experimental systems include suspended mirrors, optical microresonators, waveguides, and nano-objects. Optical measurements of mechanical motion involve quantum noise and feedback cooling. Nonlinear dynamics and multimode optomechanics are also discussed, along with quantum protocols and hybrid systems. The review highlights the role of radiation pressure in cooling and the quantum fluctuations that limit measurement precision. It discusses the standard quantum limit, quantum non-demolition measurements, and optomechanical cooling. The field has advanced rapidly, with applications in quantum information processing, precision measurements, and fundamental tests of quantum mechanics. Future directions include improving quantum coherence and exploring new systems for optomechanics.