Business does not only influence science in 21st-century America. This talk reveals how entrepreneurial science has been with us since the scientific revolution, and exposes how product marketing, patent litigation, and ghostwriting pervaded the practice of natural history and anatomy, the big sciences of the early modern era. It argues that the growth of global trade in the Dutch Golden Age gave rise to a transnational network of entrepreneurial science, connecting natural historians, physicians, and curiosi in Amsterdam, London, St Petersburg, or Danzig. These practitioners were out there to do business. They bought and sold exotica, preserved specimens, anatomical prints, and botanical atlases. This talk shows how, in their trade, Dutch naturalists relied on such mercantile innovations as postal networks and international banking, and also developed their own infrastructure for managing the long-distance, monetary exchange of scientific knowledge and curiosities. In the process, they contributed to the growth of modern science, and imbued its ethos and practices with financial undertones. Entrepreneurial rivalries, secrecy, and marketing strategies transformed the honorific, gift-based exchange system of the early modern Republic of Letters into a competitive marketplace. Emphatically, this talk also claims that trade brought about a culture of scientific debate in the Netherlands, thoroughly influencing the visual epistemology of early modern science. Market competition pitted naturalists against each other, and compelled them to develop philosophical arguments to promote the representational claims of their imaging techniques. This talk reconstructs how financial motives spurred a pamphlet war over the proper method to represent human anatomy, and also engendered the early eighteenth-century debate over Newtonian and Aristotelian color theory.