As is usually accepted for many inorganic compounds, the surface properties often play a fundamental role in the overall properties of metal oxides, in particular when the oxide materials are used in the form of fine grains. One difficulty in characterizing these surface properties is to apply the results of studies performed on ideal surfaces to the actual materials in use. A way to accept this challenge can be to successively consider initial powders, polycrystalline pellets formed after thermal or mechanical treatment of these powders and, finally, monocrystalline surfaces prepared from these powders or pellets. This principle can be applied to the study of the surface properties and reactivity of various metal oxides either used as models or having a technological interest in catalysis, electronics or energetics: doped nickel oxide, barium titanate, lanthanum-strontium manganites, etc. Some selected examples of experimental results for three kinds of investigations are presented: (i) mechanism and kinetics of nucleation and growth of ultrathin, metallic films by surface reduction of NiO and influence of the chromium segregation on the surface reactivity of Cr,O,-NiO solid solutions, (ii) effect of a high temperature treatment on the chemical surface composition of industrial BaTiO, samples. (iii) compared properties of bulk and surface layers in lanthanum-strontium manganites as a function of strontium content and biography of the materials. These analyses were performed by electron spectroscopies and diffraction associated with electron microscopy and ultrathermogravimetry.