In order to reduce empiricism in the design of adhesive bonded systems, one parameter, among many which must be determined, is the chemical composition just at the surface of the metal or alloy adherend surface. Numerous surface chemistry techniques to deduce surface composition have been developed such as secondary ion mass spectroscopy (SIMS), ion scattering spectroscopy (ISS), and Auger electron spectroscopy (AES). Each of these (as well as other) techniques when used alone can be a useful profiling tool but become far more powerful when combined with another method. The complementary nature of SIMS/ISS and SIMS/AES make them especially useful combinations. The weakness of one is generally the strength of the other. Specific examples of this strength-weakness relationship are shown for materials studied in research on adhesive bonding. Nearly every chemical and thermal treatment results in changes in surface composition. Even different treatments to pure metals can result in stoichiometry differences between anion and cation or apparent formation of various compounds on the surface. Certainly, it is necessary to know what the composition actually is at the surface in order to properly design an adhesive bonded system. The nominal composition of an alloy bears little resemblance to the surface composition, in most cases.