German journalist, publisher and politician with the Social Democratic Party of Germany (SPD). Between 1934 and 1948, Eichler wrote numerous articles under various pen names, including Martin Hart, H. M., Walter Buchholz, Walter Holz and Ernst Friesius.
In 1922, he went to work as the secretary of the socialist philosopher, Leonard Nelson, who founded the Internationaler Sozialistischer Kampfbund (ISK). He became a close confidant of Nelson. In 1923, he joined the SPD, but remained a follower of Nelson and became a member of the ISK. After Nelson’s death in 1927, Eichler became chairman of the ISK.
From 1932 to 1933, he was the editor-in-chief of the ISK’s anti-Nazi newspaper, Der Funke, which published an “Urgent Call for Unity” in June 1932 calling for support of the SPD and the KPD in the German federal election, July 1932. It was signed by 33 well-known scientists, authors and artists.
Eichler emigrated to France in 1933 after the National Socialists (Nazis) seized power. In Paris, he got involved with the Lutetia Circle, the 1935-1936 attempt of exiles to establish and support a Volksfront against the Third Reich. He also became publisher of the Reinhart Briefe, which were secretly disseminated in Germany, and the Socialistische Warte, which published articles by Hilde Meisel.
Eichler’s political activities caused him to be expelled from France in 1938. Shortly before the outbreak of war, Eichler found asylum in England, where he returned to the SPD. In London, Eichler worked at the BBC making broadcasts aimed at German workers and published Europe Speaks. In 1941, he was a founding member and board member of the Union deutscher sozialistischer Organisationen in Großbritannien, which, after the war, merged with the SPD. Toward the end of his exile in London, he worked closely with historian Susanne Miller, a German Jewish refugee, who later became his wife.
Eichler returned to Germany in 1946 and got involved rebuilding the SPD. He founded the magazine Geist und Tat, which he edited till his death on 17 October 1971. Until 1951, he also worked as editor-in-chief of the SPD newspaper, the Rheinische Zeitung.

Link to Wikipedia biography