Magnetostatics is the branch of electromagnetism that concerns magnetic fields when they are time-independent, meaning the sources of the fields are either steady currents or are completely static. The study of these steady fields is governed by foundational principles, primarily expressing the relationship between magnetic fields ($\mathbf{B}$) and the sources that create them, known as magnetic poles or currents. Key principles include the divergence-free nature of the magnetic field, which dictates the absence of magnetic monopoles, and the relationship between magnetic field strength and the circulating electrical currents. These principles are mathematically described by differential equations that allow for the calculation of magnetic flux densities within various physical geometries. The application of magnetostatic theory is critical in the design and analysis of electromagnetic devices, including transformers, motors, and solenoids, and is fundamental to understanding the behavior of materials under constant magnetic loading.