“Category books” –compilations of categorized excerpts from other books—have been a fixture of Chinese bibliography for millennia. Whether literati collectanea or commoner compendia, they have much to tell us about knowledge structures, editorial proclivities, reader interest, and lost texts. This lecture traces the itinerary of an illustrated entry on embryology from a vernacular compendia where it was featured over four centuries, backwards to its sources, forwards into new genres, and outwards into Japanese works. Digital tools can help track such itineraries, enabling us to explore why certain artefacts of knowledge traveled, with what alterations, and to what epistemic ends.