Alan Greenspan’s just-released memoir, The Age of Turbulence, is aptly titled. In his two decades as chairman of the Federal Reserve Board, Greenspan presided over Black Monday, the stock market collapse that occurred 20 years ago this month; the Asian financial crisis; the demise of Long-Term Capital Management; and the dotcom bubble.

Greenspan’s book will make headlines over the next few weeks, in part because of his surprisingly downbeat assessment of the economy and financial markets. But even though he left the Fed more than a year and a half ago, his recollections aren’t of merely historical interest. The current turmoil on Wall Street is largely a result of policy decisions he made during his final years. By keeping interest rates too low for too long, he encouraged a borrowing-fueled speculative binge, which has now given way to a credit squeeze. By failing to crack down on the mortgage industry, he allowed subprime hucksters to peddle dubious loans, which the financial industry’s math whizzes packaged for investors. Coming on top of his role in creating the internet-stock mania a decade ago, the mistakes Greenspan made—now playing out in home foreclosures and hedge fund collapses—will surely color historians’ views of his long tenure, if not his own account of it.

The 81-year-old New Yorker has lived a remarkable life. From Washington Heights, where he was born; to Times Square, where in his youth he played the clarinet in a swing band; to Wall Street, where he made his name; to Richard Nixon’s 1968 campaign, when he entered politics; to Gerald Ford’s White House, where he chaired the Council of Economic Advisers; to Foggy Bottom, where for 18 years he occupied a big office overlooking Constitution Avenue, he proved to be a brilliant survivor—the best that Washington has seen since J. Edgar Hoover.

Since leaving the Fed, he has continued to make news, if not always in ways he would like. Within weeks, he started making off-the-record appearances before select audiences: hedge fund managers, investment bankers, and the like. Inevitably, some of his remarks slipped out, causing disruptions in the markets. In February, he said a recession was possible before the end of 2007—a comment that contributed to a 416-point fall in the Dow. In May, he put the chances of a recession at one in three. Two weeks later, he rattled international bourses by saying that a bubble had developed in the Chinese stock market and a “dramatic contraction” was inevitable.

When Greenspan was chairman of the Fed, his public statements were famously delphic. While he is entitled to make a living—he reportedly charges $150,000 a speech and received an $8.5 million advance for the book—there is something jarring about his late-life discovery of clear, declaratory English. His predecessor, Paul Volcker, was barely heard from for years after he retired, and Greenspan’s failure to follow that example has perplexed some of his former colleagues. In January, the governor of the Bank of England, Mervyn King, who heads the panel that sets British interest rates, made an indirect but well-aimed swipe at Greenspan when he remarked about his own predecessor, “I’ll say only that I am very grateful to Eddie George that he has not been in the newspapers or on the radio commenting on what the committee is doing.”

Greenspan may have been acting strategically. His appearances in the headlines haven’t harmed the commercial prospects of his book, and they may have attracted some clients to Greenspan Associates, the consulting firm that he founded upon leaving the Fed. It was noticeable that shortly after he started using the R-word, Pacific Investment Management, which oversees the world’s largest bond fund, hired him as a consultant. Pimco’s chief investment officer, Bill Gross, is well-known for his bearish views on the economy and the stock market.