The difficulty in identifying provenience for Greek marble has provoked the use of many analytical techniques, but until now, none, according to the authors, has been entirely consistent or successful. They believe in the use of isotopic signatures, which, with the aid of a mass spectrometer, indicates the slight but significant and consistent variations in the relative abundance of specific oxygen and carbon isotopes from stones from each marble quarry. This analysis has helped identify forgeries as well as trace the distribution of marbles from specific Greek quarries. -- AATA