BAGHDAD, Iraq, Jan. 22 - The tools of her trade were a notebook, pen, Islamic head covering and Arabic name to pass unnoticed through Iraqi streets. Together with an interpreter and a driver, Jill Carroll, a 28-year-old American journalist, was able to slip quietly inside Iraqi society, telling stories about the lives of the Iraqis she met. But on the morning of Jan. 7, Ms. Carroll was kidnapped...