Scanning probe microscopes (SPMs) are instruments that measure properties of surfaces. They include atomic force microscopes (AFMs) and scanning tunneling microscopes (STMs). In their first applications, SPMs were used mainly for measuring 3D surface topography and, although they can now be used to measure many other surface properties, that is still their primary application. SPMs are the most powerful tools of our time for surface metrology, measuring surface features whose dimensions range from interatomic spacing to a tenth of a millimeter.

The main feature that all SPMs have in common is that the measurements are performed with a sharp probe operating in the near field, that is, scanning over the surface while maintaining a very close spacing to the surface. These instruments, specifically STMs, were the first to produce real-space images of atomic arrangements on flat surfaces. SPMs are now most commonly used to perform very precise, three-dimensional measurements on the Ångstrom-to-micrometer scale.