Otto Merk was a German engineer and archivist who worked with the records of the Peenemünde Army Research Centre (Heeresversuchsanstalt). He co-authored with journalist Ernst Klee Damals in Peenemünde (1963), the first documentary account of the centre's secret archives after their return to Germany by the United States. As a technical specialist, he oversaw the scholarly presentation of the engineering drawings, test reports, and classified photographs that form the core of the book. Detailed biographical information on Otto Merk remains scarce.