Until recently, Bethesda author Humayun Mirza never had to think about international libel law. A financier by trade, Mirza spent three decades working at the World Bank in Washington. He only turned to writing in retirement, devoting years to a biography of his father, the first president of Pakistan. Last November, his first book, "From Plassey to Pakistan: The Family History of Iskander Mirza," was published by the University Press of America.