Corrosion and weathering of ancient ceramics, plasters, glasses and glazes are described in case studies of the rehydroxylation of low fired Paleolithic ceramics, liquid-phase sintering and Ostwald ripening of Neolithic plasters, spherolite and layer formation, hydration and gelation of Near Eastern Bronze Age glasses and Parthian glazes of the soda-limi-silica family, and a Roman glass from Samaria. Examples of crazing and delayed crazing are given and the relationship of crazing to corrosion is shown. Calculations of glaze fit are shown. Degradation of high-fire stoneware and porcelainous glazes is also shown. -- CAL