Instrumented indentation basically indents a sharp tip into the surface of a material to obtain a force-displacement curve. The results provide a lot of information about the mechanical behavior of the material, including hardness, e.g., elastic moduli and plastic deformation. One key factor of instrumented indentation test is that the tip needs to be controlled by force or displacement that can be measured simultaneously throughout the indentation cycle. Current technology can realize accurate force control in a wide range. Therefore hardness can be characterized at many different length scales, from hard materials like ceramics to soft materials like polymers.