An introductory review is given of studies made by using such surface science techniques as electron spectroscopies, electron diffraction, and mass spectrometry, on adsorptions of halogen atoms or organic molecules on Ag or AgCl surfaces, on electronic structure changes with adsorption or photo-decomposition, and/or elementary distributions of silver halides. Various electron spectroscopies are discussed from a viewpoint of their application to photosensitive materials. A difficulty encountered in applying these surface science techniques to the material is also pointed out.