This chapter introduces tribology and discusses scale effects at macro-, micro-, and nanoscale. It highlights the lack of international standardization in micro- and nanotribology. With the increasing advance of computational capabilities, different numerical methods have been employed to predict the tribological behavior at the nanoscale. Analytical methods such as molecular dynamics (MD), Monte Carlo, and ab initio calculations are used by different research groups. It is usual that researchers speak about tribology in terms of a scale, such as macrotribology, microtribology, and nanotribology. The three most common methods used for the tribological characterization at micro- and nanoscale are the surface force apparatus, the lateral force microscope, and the Triboindenter. The Technical Report ISO/TR 11811 is titled “Nanotechnologies: Guidance on methods for nano- and microtribology measurements“. This report describes procedures for undertaking these kinds of measurements, and provides guidance on the effects of parameters on test results.