This chapter covers the electrostatic phenomena caused by electric chargesElectric charge in a vacuum. First, we learn about the Coulomb forceCoulomb force that works between electric chargesElectric charge. This force on a given charge is caused by an electrical distortion in space that is produced by other electric chargesElectric charge. This distortion is represented by the electric fieldElectric field. The local electric fieldElectric field produced by electric chargesElectric charge is described by Coulomb’s lawCoulomb’s law. On the other hand, Gauss’s lawGauss’s law describes the global relationship between the electric chargeElectric charge and the electric fieldElectric field. The electric fieldElectric field is expressed by the gradientGradient of the electric potentialElectric potential and has a nature of a field with no rotationRotation. The equipotential surfaceEquipotential surface is a virtual surface on which the electric potentialElectric potential is the same. The electric fieldElectric field is perpendicular to the equipotential surfaceEquipotential surface. We also learn the electrical properties of the electric dipoleElectric dipole, i.e., a pair of positive and negative electric chargesElectric charge of the same magnitude, which appears under various conditions in electric phenomena.