Today, the production of knowledge in the experimental life sciences relies crucially on the use of biological data collections, such as DNA sequence databases. These collections, in both their creation and their current use, are embedded in the experimentalist tradition. At the same time, however, they exemplify the natural historical tradition, based on collecting and comparing natural facts. This essay focuses on the issues attending the establishment in 1982 of GenBank, the largest and most frequently accessed collection of experimental knowledge in the world. The debates leading to its creation—about the collection and distribution of data, the attribution of credit and authorship, and the proprietary nature of knowledge—illuminate the different moral economies at work in the life sciences in the late twentieth century. They offer perspective on the recent rise of public access publishing and data sharing in science. More broadly, this essay challenges the big picture according to which the rise of experimentalism led to the decline of natural history in the twentieth century. It argues that both traditions have been articulated into a new way of producing knowledge that has become a key practice in science at the beginning of the twenty-first century.