The paper first gives a brief review of the fundamentals of localized corrosion on multicomponent, multiphase alloys based on a knowledge of the bulk structure and the significance of such knowledge in developing materials with improved corrosion resistance. Recent advances in investigating the near surface microstructure of aluminum alloys are next discussed along with the developing understanding of the relationship between the surface structure, electrochemistry, corrosion behavior, and surface quality in general, In particular, recent electrochemical work and TEM studies of common types of architectural alloys and their model analogues revealed the presence of a surface layer with properties very different from the bulk. The surface layer is a result of the thermomechanical processing of the wrought product, especially exposure to high shear and elevated temperatures, and it is characterized by a refined grain structure with grain sizes one to two orders of magnitude smaller than the bulk grains. These are intermixed with rolled-in oxide particles and a very fine distribution of secondary intermetallics, which precipitate preferentially in the surface layer as a result of heat treatment. The significance of such layers to localized corrosion is discussed along with possible significance also to other type of surface properties, such as in relation to adhesive bonding and optical quality.