Coincidence techniques have been fruitfully employed in many areas of physics. They are now beginning to be used in the study of surfaces. In electron spectroscopy, their appeal is that they can be used to distinguish between processes, and, in some cases, to completely describe single events. The interaction between surface atoms and electrons is complex, with many possible interactions. The coincidence technique can be used to reduce the number of possibilities and so to produce spectra that are more easily interpreted. However, the high density of atoms on a surface necessarily means that there is a high density of emitted inelastic electrons that appear as background in the spectra. These, and other effects, make it difficult to perform coincidence spectroscopy from surfaces, which explains why there have been relatively few experiments undertaken to date. The progress in developing coincidence experiments is reviewed, along with a description of the understanding that has come from it.