The Bourne Identity (Jason Bourne, #1) by Robert Ludlum

He was dragged from the sea, his body riddled with bullets. There are a few clues: a frame of microfilm surgically implanted beneath the skin of his hip; evidence that plastic surgery has altered his face; strange things he says in his delirium, which could be code words. And a number on the film negative that leads to a bank account in Zurich, four million dollars, and a name for the amnesiac: Jason Bourne. Now he is running for his life. A man with an unknown past and an uncertain future, the target of assassins and at the heart of a deadly puzzle. He's fighting for survival and no one can help him - except the one woman who once wanted to escape him . . .