Historian of esotericism Nicholas Goodrick-Clarke characterises Mills as a "Nazi sympathiser". Mills' trip to Germany included a visit to the Brown House where, without appointment, he met Adolf Hitler "talking" (Mills would later recount) "to some of his confreres". At the 1944 Australia First enquiry, Mills claimed that Hitler had impressed him as a "kindly man" who "seemed to have the respect of his men and appeared kind to them." In Germany, Mills also met followers of General Erich Ludendorff, the famous First World War strategist and conspiracy theorist who was also, like Mills, virulently anti-Semitic.