Journalist Jane Mayer’s book “Dark Money: The Hidden History of the Billionaires Behind the Rise of the Radical Right” explores the shadowy realm of excessive wealth and how it affects American politics. Mayer reveals a network of conservative billionaires that fund groups intentionally to influence think tanks, courts, statehouses, academia, Congress, and the presidency. This network includes the Koch, Scaife, Olin, and Bradley families.