Tribology—the science of friction, wear, and lubrication—is of considerable importance for all technical applications where moving bodies are in contact. Nonetheless, little progress has been made in finding an exact atomistic description of friction since Amontons proposed his empirical macroscopic laws over three centuries ago. The advent of new experimental tools, such as the friction force microscope, however, has enabled the investigation of frictional forces down to the atomic scale. Recently, this tool has been used to measure the friction of nanoparticles sliding over flat surfaces, thereby enabling a much larger range of material combinations and interface contact areas to be studied. These advances offer new insight into the atomistic concepts of friction.