Leopold Schwarzschild (8 December 1891, in Frankfurt am Main, Germany – 2 October 1950, in Santa Margherita Ligure, Italy) was a German author.
A review in Foreign Affairs called it an "attempt to reinterpret the history of the two inter-war decades in terms of the progressive disintegration of Allied resistance to Germany's military revival".
Wells, who called Schwarzschild "superficially intelligent and massively stupid", and Michael Foot, who denounced it as "a facile, scintillating treatise which...has received applause from those weary brains which prefer the dismal past to the adventurous future".
However, Popper added a note to the fifth edition: "Some years after I wrote this...Leopold Schwarzschild's...The Red Prussian...became known to me...it contains documentary evidence, especially from the Marx-Engels correspondence, which shows that Marx was less of a humanitarian, and less of a lover of freedom, than he is made to appear in my book.
[6] Isaiah Berlin said that "Schwarzschild's evidence is, so far as it goes, accurately and even pedantically sifted; his research is minute, his scholarship impressive...[Marx] emerges as an almost incredible compound of treachery, envy, sadism, megalomania and paranoia".