A history of American law in the 20th century. It describes the explosion of law over the past century into almost every aspect of American life. Since 1900 the centre of legal gravity in the United States has shifted from the state to the federal government, with the creation of agencies and programmes ranging from Social Security to the Securities Exchange Commission to the Food and Drug Administration. Major demographic changes have spurred legal developments in such areas as family law and immigration law. Dramatic advances in technology have placed new demands on the legal system in fields ranging from automobile regulation to intellectual property.