The development of scanning probe microscopes in the early 1980s brought a breakthrough in imaging, throwing open a window into the world at the nanoscale. The key idea is to scan an extremely sharp tip over a substrate and to record at each location the strength of the interaction between tip and surface. In scanning force microscopy, this interaction is—as the name implies—the force between tip and structures on the surface. This force is typically determined by measuring how the dynamics of a vibrating tip changes as it scans over objects deposited on a substrate. A common analogy is tapping a finger across a table and sensing objects placed on the surface.