Hartog van Geuns was a son of Eliazer van Geuns and Frederika Tas. He was printer and a typographer by profession and unmarried. He stayed in September-early October 1942 in labour camp Conrad near Staphorst. See Gert-Jan Westhoff, Forced Labour in Staphorst. Jewish Labour camps in Staphorst and Rouveen.(Kampen 2012, page 120)
Known is that all Jewish Labour camps were closed down on 3 October 1942 by order of the German occupier and that all Jewish forced labourers were carried off to Westerbork Also Hartog van Geuns; he was deported from Westerbork to Auschwitz on 5 October 1942 and on arrival there again selected as forced labourer. In the end, he has lost his live eventually somewhere in Mid Europe on 31 May 1945.
Sources include the City Archive of Amsterdam, family registration card of Eliazer van Geuns, archive card of Hartog van Geuns; the file cabinet of the Jewish Council, registration card of Hartog van Geuns and death certificate Amsterdam, nr. 21 from A register 113, fol. 4 dated 14 June 1957 for Hartog van Geuns.