In previous chapters a broad variety of methods has been treated which could be easily grouped into spectroscopic methods or techniques employing some sort of interaction between electromagnetic radiation and the electrochemical interface. Various techniques remain which are hard to assign to any of the families of methods presented so far. This is partly caused by the fact, that some of these methods combine optical, i.e. spectroscopic, details with experimental features providing spatial resolution or to the fact, that surface properties like e.g. electrical conductivity are measured which have no direct or obvious relationship to spectroscopic methods.