Nathan Polak was a son of Hartog Polak and Rozetta Hijmans. He married in Amsterdam on 22 January 1913 to Sientje Coster, daughter of Mozes Abraham Coster and Susanna Bachrach. The couple had two children together: Susanna and Rozetta. The latter has surived the Holocaust. Sientje Coster passed away…
In addition, a Jokos file (number 32771) on this family is at the Amsterdam Municipal Archive. Access is subject to authorization from the Stichting Joods Maatschappelijk Werk.
Eva Polak-Coster is na de dood van haar halfzus Sientje Coster (die getrouwd was met Nathan Polak en de moeder is van Susanna van der Kar-Polak en het overlevende kind) getrouwd met Nathan Polak.