This article explains firm emergence and the role of firms in the market structure using the productive power of specialization. Based on productivity efficiencies through technological specialization, a model for firm emergence is drafted alongside Coasean transaction cost theory. I find that transaction costs cannot explain firm emergence, but the entrepreneurial specialization perspective here adopted provides a promising approach to understanding the firm's function to the entrepreneur and its internal organization and capabilities. It suggests a foundational framework for studying the creation of capabilities and the interplay between markets, firms, and entrepreneurs. Copyright © 2014 John Wiley & Sons, Ltd.