 Despite its prominent position in the rich, if fragile, intellectual culture of inter-war Vienna and most likely due to its radical doctrines, the Vienna Circle found itself virtually isolated in most of German speaking philosophy. The one exception was its contact and cooperation with the Berlin Society for Empirical (later: Scientific) Philosophy (the other point of origin of logical empiricism). The members of the Berlin Society sported a broadly similar outlook and included, besides the philosopher Hans Reichenbach, the logicians Kurt Grelling and Walter Dubislav, the psychologist Kurt Lewin, the surgeon Friedrich Kraus and the mathematician Richard von Mises. (Its leading members Reichenbach, Grelling and Dubislav were listed in the Circle’s manifesto as sympathisers.) At the same time, members of the Vienna Circle also engaged directly, if selectively, with the Warsaw logicians (Tarski visited Vienna in 1930, Carnap later that year visited Warsaw and Tarski returned to Vienna in 1935). Probably partly because of its firebrand reputation, the Circle attracted also a series of visiting younger researchers and students including Carl Gustav Hempel from Berlin, Hasso Härlen from Stuttgart, Ludovico Geymonat from Italy, Jørgen Jørgensen, Eino Kaila, Arne Naess and Ake Petzall from Scandinavia, A.J. Ayer from the UK, Albert Blumberg, Charles Morris, Ernest Nagel and W.V.O. Quine from the USA, H.A. Lindemann from Argentina and Tscha Hung from China. (The reports and recollections of these former visitors—e.g. Nagel 1936—are of interest in complementing the Circle’s in-house histories and recollections which start with the unofficial manifesto—Carnap, Hahn and Neurath 1929—and extend through Neurath 1936, Frank 1941, 1949a and Feigl 1943 to the memoirs by Carnap 1963, Feigl 1969a, 1969b, Bergmann 1987, Menger 1994.)