Lothar Bisky was a German politician. He was the chairman of the Party of Democratic Socialism (PDS), the successor of East Germany's Socialist Unity Party (SED). In June 2007 he became co-chairman of The Left party, formed by a merger of the PDS and the much smaller Labour and Social Justice – The Electoral Alternative. From 2007 until 2010 he was the President of the Party of the European Left. Also, he was the Publisher of the socialist newspaper Neues Deutschland.

The Party of Democratic Socialism was a left-wing populist political party in Germany active between 1989 and 2007. It was the legal successor to the communist Socialist Unity Party of Germany (SED), which ruled the German Democratic Republic as the de facto sole legal party until 1990. From 1990 through to 2005, the PDS had been seen as the left-wing "party of the East". While it achieved minimal support in western Germany, it regularly won 15% to 25% of the vote in the eastern new states of Germany, entering coalition governments with the Social Democratic Party of Germany in the federal states of Mecklenburg-Vorpommern and Berlin.