The paper discusses the definition and characteristics of geomagnetic storms, their relationship with substorms, and the factors influencing their occurrence. It begins by defining a geomagnetic storm as an interval of time when a strong and prolonged interplanetary electric field leads to significant energization in the magnetosphere-ionosphere system, resulting in an intensified ring current that exceeds a key threshold of the Dst index. The paper reviews the storm-substorm relationship, noting that while the physics of this relationship is not fully understood, basic mechanisms are well established. It also provides recommendations for future improvements in monitoring geomagnetic indices and the solar wind near Earth. The paper then explores the historical development of geomagnetic storm research, the interplanetary origin of storms, and the role of the interplanetary medium, particularly the IMF $B_{S}$ component. It discusses the Dst index and its relationship with magnetospheric parameters, the classification of storms by intensity, and the role of the solar wind in storm formation. The paper also addresses the seasonal and solar-cycle distribution of storms, noting that intense storms tend to occur during solar maximum and have a seasonal distribution with peaks at the equinoxes. The paper reviews the relationship between storms and substorms, noting that while substorms can occur independently of storms, they often contribute to the development of geomagnetic storms. It discusses the energy transfer processes in the magnetosphere, the role of the ring current in storm development, and the factors that influence the efficiency of energy injection into the ring current. The paper also addresses the challenges in understanding the storm-substorm relationship and the need for further research to improve the accuracy of storm predictions and monitoring.The paper discusses the definition and characteristics of geomagnetic storms, their relationship with substorms, and the factors influencing their occurrence. It begins by defining a geomagnetic storm as an interval of time when a strong and prolonged interplanetary electric field leads to significant energization in the magnetosphere-ionosphere system, resulting in an intensified ring current that exceeds a key threshold of the Dst index. The paper reviews the storm-substorm relationship, noting that while the physics of this relationship is not fully understood, basic mechanisms are well established. It also provides recommendations for future improvements in monitoring geomagnetic indices and the solar wind near Earth. The paper then explores the historical development of geomagnetic storm research, the interplanetary origin of storms, and the role of the interplanetary medium, particularly the IMF $B_{S}$ component. It discusses the Dst index and its relationship with magnetospheric parameters, the classification of storms by intensity, and the role of the solar wind in storm formation. The paper also addresses the seasonal and solar-cycle distribution of storms, noting that intense storms tend to occur during solar maximum and have a seasonal distribution with peaks at the equinoxes. The paper reviews the relationship between storms and substorms, noting that while substorms can occur independently of storms, they often contribute to the development of geomagnetic storms. It discusses the energy transfer processes in the magnetosphere, the role of the ring current in storm development, and the factors that influence the efficiency of energy injection into the ring current. The paper also addresses the challenges in understanding the storm-substorm relationship and the need for further research to improve the accuracy of storm predictions and monitoring.