By the middle of the 20th century, investigative journalism featured teams of professional reporters combing through government statistics, court records, and business reports acquired by visiting state houses, archives, and dusty courthouse basements; or obtaining official or leaked confidential documents. These lists of numbers and accounts in the ledgers and filing cabinets of the world’s bureaucracies have always been a rich source of data, long before data could be published in a digital form and shared instantaneously around the world. Database-driven journalism arrived in most newsrooms in a real sense over three decades ago, when microcomputers became commonplace in the 1980s”although the first pioneers used punch cards. When computers became both accessible and affordable to newsrooms, however, the way data could be used changed how investigations were conducted, and much more. Before the first laptop entered the newsroom, technically inclined reporters and editors had found that crunching numbers on computers on mainframes, microcomputers, and servers could enable more powerful investigative journalism.