Short answers, pulled from the story.
Alan Greenspan is an American economist who served as the 13th chairman of the Federal Reserve from 1987 to 2006, the second-longest tenure in that position behind only William McChesney Martin. He was first nominated by President Ronald Reagan in August 1987 and was reappointed by Presidents George H. W. Bush, Bill Clinton, and George W. Bush.
The Greenspan put refers to the Federal Reserve's monetary policy practice under Greenspan of providing liquidity to cushion financial markets from severe losses. Critics argued that the policy allowed banks to repeatedly blow up speculative bubbles and then borrow cheaply from the Fed to start again, making it very difficult for banks to lose money and encouraging excessive risk-taking.
Greenspan was introduced to Ayn Rand in the early 1950s by his first wife, Joan Mitchell, and became a member of Rand's inner circle, the Ayn Rand Collective, reading Atlas Shrugged while it was being written. He contributed essays to her 1966 book Capitalism: The Unknown Ideal and remained friends with Rand until her death in 1982, though later critics argued his conduct at the Federal Reserve contradicted Objectivist free-market principles.
In congressional testimony on the 23rd of October 2008, Greenspan acknowledged he had been "partially" wrong in opposing regulation and said he had found "a flaw" in his free-market ideology. When Representative Henry Waxman asked if his worldview had not been working, Greenspan replied: "Absolutely, precisely."
Greenspan later admitted that he "really didn't get it until very late in 2005 and 2006." In 2007 he warned of "large double digit declines" in home values "larger than most people expect." A 2004 speech in which he suggested homeowners consider adjustable-rate mortgages drew sustained criticism after the subprime mortgage industry collapsed in March 2007.
Greenspan published The Age of Turbulence: Adventures in a New World on the 17th of September 2007, writing it in longhand mostly while soaking in the bathtub. He praised Bill Clinton above all other presidents for his "consistent, disciplined focus on long-term economic growth" and criticized George W. Bush, Dick Cheney, and the Republican Congress for abandoning fiscal discipline, writing: "They swapped principle for power. They ended up with neither."