Since the mid-nineteenth century, classifications of knowledge have opposed the bookish, history-conscious humanities to the empirical, amnesiac sciences. Yet in the sciences of the archive, the library stands alongside the laboratory, the observatory, and the field as an important site of research. The sciences of the archive depend on data and specimens preserved by past observers and project the needs of future scientists in the creation of present collections. Starting in the early modern period, distinctive practices of weaving together the data of the archives and of present investigation have created a hybrid hermeneutics of reading and seeing.