In "Mein Kampf", Hitler mentioned the United States only occasionally and even with contempt. They were, to him, a "racially degenerate" society that will continue to see its demise. In his second book, however, Hitler describes the United States as a dynamic and "racially successful" society that has eugenics, racial segregation practices, and an exemplary immigration policy at the expense of "inferior" immigrants from Southern and Eastern Europe. Why this change occurred in Hitler's attitude between 1924 and 1928 is unknown. Historians have noted that Hitler was notoriously poorly informed about the world outside Germany and, at the time of the writing of "Mein Kampf", he probably knew little about the United States. Hitler's knowledge of the U.S. came especially from the Western novels of Karl May he read. This seems to have changed by 1928; Hitler would have heard of the prosperity and industrialization in the United States, as well as the Immigration Act of 1924, and of racial segregation.