Some years ago one of us wrote, “A glance at a chipped stone tool is enough to see that stone is a subtractive medium” (Shott 1994: 69). The statement bordered on a truism but was worth making in any event. Flakes, the small pieces of stone struck from larger objective pieces, were the subject then; the context was their abundance and diversity as generated in the production, use, and resharpening of tools. Flake analysis makes no sense without understanding the places that flakes occupy in the reduction process.

But the reductive quality of stone also informs the analysis of objective pieces themselves, not least finished tools. Accordingly, tools also are a legitimate subject of reduction studies. A deceptively profound truism worth stating once is worth rephrasing: a glance at a chipped stone tool is enough to see that it was reduced from a larger piece. But the restatement itself requires elaboration. Trivially, tools were reduced from larger objective pieces in the process of production. No one has doubted this since archaeologists demonstrated human agency in the production of stone tools. Yet many tools were further retouched by resharpening, and so continued to experience reduction during use. This is the “reduction thesis” (Shott 2005), which archaeologists did not always appreciate in the past.

This book is a milestone in the development of reduction analysis. Originating in pioneering studies such as Hoffman's (1985), until recently reduction analysis was conducted in isolation by few archaeologists.