Stone tools form an important part of the archaeological record, and implement petrology studies attempt to provide information about their manufacture, use, and distribution in prehistory. By accumulating information through careful observation and experiment, archaeologists are gradually increasing their sensitivity to and understanding of stone tools as cultural markers. Thin-section under polarizing microscopy, x-ray diffraction, x-ray fluorescence, and microprobe analysis are useful methods in this area of study. Back-scatter techniques and the advantages of scanning electron microscopy (SEM) are discussed. Policies need to be implemented to keep the field of implement petrology abreast of changes in historic interpretation.