One of the distinctive features of the Austrian School of Economics has been its emphasis on the entrepreneur as central to the market process. One 20th century Austrian whose work is normally not thought of as making a major contribution to the Austrian theory of entrepreneurship is Ludwig Lachmann. However, a careful reading of his 1956 book Capital and its Structure can tease out a theory of the function of the entrepreneur that is distinctly different from that of Israel Kirzner, yet still clearly situated in an Austrian conception of the market process. In this contribution, I want to emphasize two points that have been raised by previous work on Lachmann, but not explored in any detail. The first is that Lachmann’s conception of entrepreneurship is deeply bound up with the need to engage in monetary calculation thanks to the heterogeneity of capital and uncertainty of the future. For Lachmann, the key function of the entrepreneur is to “specify” the uses of capital goods. Such specification requires the use of money prices and what Mises called monetary calculation. The second contribution is to offer more detail on the way in which entrepreneurs both creatively specify and re-specify the uses of their capital goods in response to profit and loss signals. The constant shuffling and reshuffling of capital goods, of which coming up with new products or new twists to old ones are a part, is the essence of Lachmann’s implicit vision of entrepreneurship. For Lachmann, entrepreneurship is bound up with resource ownership and deployment through the creation and revision of plans in ways that are much more active than Kirzner’s conception of the entrepreneur.