The metal-oxide interface is a crucial zone in the fundamental understanding of oxide growth and growth instabilities. However, obtaining fundamental information on this buried interface has proven extremely difficult using modern surface and interfacial characterization methods. Using copper oxide growth over copper metal, examined between RT and 250C, as a model system, we have delineated the fundamental physical chemical processes that determine the oxide growth and instabilities at the metal-oxide interface. Application of controlled thermal growth studies in combination with linear sweep voltammetry (LSV) has allowed experimental access to the metal-oxide interface with surprising characterization capabilities. The methodologies involved and the physical chemical phenomena will be discussed in context of the application of modern surface characterization methods including pulsed field desorption mass spectrometry, XPS combined with depth profiling and angular resolved methods. The evolution and alteration of the precursor oxide that develops at low temperatures <75C will be explained on the basis of previously observed metal oxide interfacial phenomena involving coupled bulk and surface reactions. The nature of the interfacial zone will be discussed with electron transfer and oxygen absorption models that are applicable to oxide growth and instabilities in general.