"This is the same furniture I got when I became chief executive of Siemens in 1992." Heinrich von Pierer knocks on a wooden table that was made in Erlangen, his home town in Bavaria. His Munich office is unfussy and exudes efficiency - as might be expected from one of Germany's most influential business leaders. Von Pierer, 65, is now the chairman of the €57bn (£40bn) industrial giant Siemens, as well as chief economic adviser to Chancellor Angela Merkel and a member of the boards of Volkswagen, Deutsche Bank and ThyssenKrupp, Germany's largest steel producer. In his keynote address at The Institute of International Studies, UC Berkeley, he ranged across subjects like the genocide of the Native Americans, Thailand and the US Civil War, suggesting movies should resemble "the great Hindu and Buddhist ideographs I saw in the temple walls of Southeast Asia. Massive paintings and murals telling the common tales, well-known tales of danger, fear, death, heroes, elephants, love, the birth of children and new kings, new dreams."Meanwhile, World Trade Center, described by Fox News commentator Cal Smith as: "One of the greatest pro-American, pro-family, pro-faith, pro-male, flag-waving, God Bless America films you will ever see," has once again shoved America's greatest renegade filmmaker back on to centre stage. But in the likelihood that the Right now feel they can embrace Stone as one of their own, they should not lose sight of the fact that they have a guerrilla in their midst..

He was arrested again in May 2005 in Los Angeles for possession of a small quantity of marijuana, by which time waggish commentators had taken to calling him Oliver Stoned.As a filmmaker, Stone's rehabilitation has proved more dramatic. Widely read in American history, especially in the murkier areas he says have been sanitised or reconstructed for political and social expediency, Stone is a formidable exponent of the right of free speech and a champion against injustice He is also a proud American. In 1999 he was arrested and pleaded guilty to drug possession and no contest to driving under the influence He was ordered into a rehabilitation programme. This reached its apotheosis in Natural Born Killers, where his experiments in multi-formats (using VHS, 8mm and 70mm film, B&W, manipulated colour and animation) seemed almost out of control.Fellow director Quentin Tarantino, who had written the script of Natural Born Killers, disliked Stone's treatment of his work so much he requested his name be removed from the credits.As the 1990s wore on, Stone became more disenchanted with Hollywood and with the Bush government - "An ex-alcoholic who believes in Jesus What could be more dangerous?" he once said. He won his first Oscar for Best Adapted Screenplay for Midnight Express.

The 1980s were to prove his most successful decade, with Platoon (for which he won the Best Director Oscar), Wall Street and Born on the Fourth of July (for which he bagged a second Best Director Oscar).In 1991, his rock biopic of Jim Morrison, The Doors, ushered in a new era of psychedelia for Stone, who was allegedly experimenting with magic mushrooms and other hallucinogens. In 1981 he made The Hand with Michael Caine but it wasn't until 1986 that he found his distinctively abrasive voice in Salvador. He requested combat duty and was assigned to the 25th Infantry Division, where he changed his name to "Bill" on the grounds that "Oliver" wasn't macho enough - and then the 1st Cavalry Division. Twice wounded in action, he was awarded the Bronze Star with "V" device for valour and the Purple Heart with Oak Leaf Cluster.He has three children, two sons from his 12-year marriage to Elizabeth Stone and a daughter by his girlfriend, Chong Son Chong.Stone began his career writing scripts for horror movies and made his debut as feature director with Seizure in 1974. He attended The Hill School, Yale University and New York University.