American bankers supplied Adolf Hitler with millions of dollars to help build up his Nazi party. Warburg was a joint owner of the New York bank, Kuhn Loeb & Cie; he describes three conversations he held with Hitler at the request of American financiers. This book was originally publisher in Holland in 1933, shortly before Warburg's death.
Book published by a pseudonymous author, "Sidney Warburg", in 1933, in Holland, in Dutch. The book was immediately removed from circulation after a few days. 3 copies survived, one of which was translated in German, and from that translated copy was derived this book in English.
Sutton reports that the New York Times published an article about the book on Nov 24, 1933 with the title "HOAX ON NAZIS FEARED".
I never knew about this book, until I read Sutton's "Wall Street and the Rise of Hitler". He has an entire chapter on it and puts forth the argument that this must be the work of the government of one of the countries who feared they would be attacked by the Nazis (France and the Soviet Union, or a faction of the US government!) and wanted to prevent it from happening by disclosing this information.
For more read it yourself or better consult the page on Wikipedia /wiki/Sydney_Warburg