The document discusses how interactions between craft and commercial firms with narrow and broad targets foster market evolution. It outlines how firms elaborate, translate, and transform their products and practices over time, leading to greater diversity, broader skills and knowledge, and an expanded meaning system in the market. The document also categorizes firms into craft specialists, commercial specialists, craft generalists, and commercial generalists based on whether they pursue aesthetic perfection or profit maximization and whether they have a narrow or broad target.