This review discusses the experimental study of spin states in quantum dots, focusing on the control and measurement of individual electron spins. Quantum dots are nanoscale structures in semiconductor materials that can trap a small number of electrons. These systems allow for precise control over individual electrons, enabling the study of quantum phenomena such as spin superpositions, entanglement, and quantum measurements. The review covers various methods for extracting spin properties, including spin filling from magnetospectroscopy and excited-state spectroscopy, as well as techniques for spin manipulation and measurement. It also discusses the physics of spin-orbit and hyperfine interactions, which affect spin coherence and dephasing. The review highlights the importance of spintronics and quantum information processing, where individual spins can be used as qubits. The study of spin states in quantum dots has led to significant advances in understanding quantum mechanics and has potential applications in quantum computing and spintronics. The review also discusses the challenges of controlling individual spins and the importance of experimental techniques for spin manipulation and measurement. The review concludes with a perspective on the future of spin-based quantum technologies.This review discusses the experimental study of spin states in quantum dots, focusing on the control and measurement of individual electron spins. Quantum dots are nanoscale structures in semiconductor materials that can trap a small number of electrons. These systems allow for precise control over individual electrons, enabling the study of quantum phenomena such as spin superpositions, entanglement, and quantum measurements. The review covers various methods for extracting spin properties, including spin filling from magnetospectroscopy and excited-state spectroscopy, as well as techniques for spin manipulation and measurement. It also discusses the physics of spin-orbit and hyperfine interactions, which affect spin coherence and dephasing. The review highlights the importance of spintronics and quantum information processing, where individual spins can be used as qubits. The study of spin states in quantum dots has led to significant advances in understanding quantum mechanics and has potential applications in quantum computing and spintronics. The review also discusses the challenges of controlling individual spins and the importance of experimental techniques for spin manipulation and measurement. The review concludes with a perspective on the future of spin-based quantum technologies.