  Several letters by Kurt G\"odel and Johann (J\'anos) von Neumann from the (so
far uncatalogued) archive of Abraham (Adolf) Fraenkel at the National Library
of Israel are published and discussed. These include two fragments by G\"odel
of special interest, since they concern the relationship between G\"odel's
incompleteness theorem and work by Herbrand, Presburger, and Zermelo, as well
as a long letter from von Neumann from 1923 explaining his own approach to the
axiomatization of set theory.
