This essay argues for a more reflexive understanding of collected works in the history of science, and the history of the book more broadly. It touches upon a large number of cases, which show that the significance of collected editions is not understood when they are considered purely as purveyors of editorially purified texts. They can be monuments of national pride, an attempt by a publisher or editor to increase his status, or typographical reference objects. By introducing the juxtaposition of opera and opuscula the paper also argues that the special status of collected works is best understood as a phenomenon of post-Gutenberg print culture.