In 1970, Ted Williams – a medical missionary who had been running a small hospital at Kuluva in the West Nile region of Uganda for decades – was approached by the International Agency for Research on Cancer (IARC) to help establish a major study on the possible role of Epstein–Barr Virus in the aetiology of Burkitt’s lymphoma (BL). At the time, there was intense global interest in BL, as the cancer promised to be the first shown to have a viral aetiology. IARC centred its project at Kuluva Hospital and in the West Nile district because of Williams’ unusually detailed and accurate records. Williams was a meticulous record-keeper, who relied on various methods of data collection, from collecting and comparing to selecting and sorting. His paper-based archives and recording practices provide a rare window onto epidemiological knowledge production in East Africa in the decades before computing reshaped medical record-keeping. By tracing the ‘sociomaterial paper trail’ of Williams’s work, this paper examines how persona, place, and paper intersected in the making of medical knowledge, and how the researcher’s persona shapes the kinds of epidemiological data that are ultimately produced.