Bertelsmann AG is a multinational media corporation founded in 1835, based in Gütersloh, Germany. The company operates in 63 countries and employs 102,983 workers (as of December 31, 2009). In 2008 the company reported a €16.118 billion consolidated revenue and an operating EBIT of €1.568 billion. Among its some 2000 subdivisions, subsidiaries, and branches are Random House, RTL Group, Gruner + Jahr, Arvato, and BMG Rights Management.

Bertelsmann is majority owned (77.4%) by the Bertelsmann Foundation, a non-profit organisation and political think tank founded by the Mohn family. The Mohn family owns the remaining 22.6% of the company.

The C. Bertelsmann Verlag was founded as a publishing house and print shop in July 1835 by Carl Bertelsmann. At first Bertelsmann concentrated on Christian songs and books. In 1851, led by Carl Bertelsmann's son Heinrich, the company began publishing novels. During the following years Bertelsmann expanded steadily. By 1939 the publishing house employed 401 people. During World War II, Bertelsmann was the biggest single producer of Nazi propaganda. Its owner, Heinrich Mohn, is said to have belonged to a group that donated money to the Nazi squadron SS. At the end of World War II, the publishing house was closed for some time because of illegal paper-trading. During the Nazi period, it published books by Nazi authors such as Will Vesper (who did the commemorative speech at the 1933 book burning) and Hans Grimm. In 1947, the company was re-founded by Reinhard Mohn, fifth generation of the Bertelsmann family. In 2002 a commission appointed by the company itself found that it had co-operated closely with the Nazis during the war and used Jews as cheap labour.