Mark J. Penn (born September 10, 1954), is the worldwide CEO of the public relations firm Burson-Marsteller and president of the polling firm Penn, Schoen and Berland Associates. In September 2007, he released a book titled Microtrends: The Small Forces Behind Tomorrow's Big Changes, which examines small trends sweeping the world. He was Hillary Clinton's chief strategist for most of her 2008 presidential campaign, for which his firm received $13 million, until he resigned on April 6, 2008. He remains a key pollster and adviser to the campaign.