While the lateral spatial resolution of far-field optical techniques is limited by diffraction at a few hundreds of nanometres, Scanning Thermal Microscopy (SThM) allows real nanoscale thermal imaging. SThM techniques are based on Scanning Probe Microscopy (SPM) methods, with spatial resolutions depending on the characteristic lengths associated with the heat transfer between the small probes and the samples to be characterized. The probes can be tailored with tips of curvature radii in the range of a few tens of nanometres. The first instrument was invented in 1986, shortly after the discovery of the Scanning Tunnelling Microscope¹  (STM) by Williams and Wickramasinghe, and was termed the Scanning Thermal Profiler²  (STP). Its goal was to extend the possibilities of imaging topography because the STM was limited to insulators. Although the STP was not intended for mapping temperature distributions of surfaces, it stimulated intense efforts to develop SPM-based techniques in the thermal area. Scanning Thermal Microscopy is now an integral part of the experimental landscape in sub-micron heat-transfer studies and has found a wide range of applications.