Friction is a fundamental force that emerges from the interaction between two surfaces that are in contact. It is a complex phenomenon that depends on several factors, such as the nature of the materials involved, the temperature, the pressure, and the speed of the motion. Friction results from the interlocking of asperities or irregularities on the surfaces, as well as from adhesion, deformation, and thermal effects. Friction can be described by several models, such as Amontons’s laws, Coulomb’s law, or the Tomlinson model. Friction plays a crucial role in various natural and industrial processes, such as locomotion, adhesion, braking, tribology, and lubrication. The study of friction is essential to understand the behavior of materials, the design of machines, and the optimization of energy efficiency.