The once purposely opaque Alan Greenspan, longtime chairman of the Federal Reserve, is startlingly clear this week as he promotes his new book, “The Age of Turbulence: Adventures in a New World.” But without his immensely powerful position, Mr. Greenspan is showing himself not only to be mortal but occasionally silly.

For instance, his 2001 testimony to Congress in support of a tax cut while the budget surplus continued came as a crucial boost to President Bush’s tax-cut package. In his book, Mr. Greenspan now says, “I’d misjudged the emotions of the moment. We had just gone through a constitutional crisis over an election – which, I realized in hindsight, is not the best time to try to put across a nuanced position based on economic analysis.” He told Leslie Stahl of “60 Minutes” that he favored a tax cut, but not necessarily the Bush tax cut, an explanation that is less nuance than avoidance.

In his memoir, he said plainly, “I am saddened that it is politically inconvenient to acknowledge what everyone knows: the Iraq War is largely about oil.” In yesterday’s Washington Post, he clarified that, saying of President Bush and Vice President Dick Cheney, “I’ve never heard them basically say, ‘We’ve got to protect the oil supplies of the world,’ but that would have been my motive” for going to war. Unlike weapons of mass destruction, at least this nation was sure Iraq had oil; but establishing a policy of invading countries that have desirable natural resources seems sort of archaic.

After three years and 13 rate cuts, Mr. Greenspan raised the prime interest rate in 2004 saying, “Our hope was to raise mortgage rates to levels that would defuse the boom in housing, which by then was producing an unwelcome froth.” But he was putting the lid on after the froth had left the cup, and 16 subsequent rate hikes couldn’t do what lax lending practices finally achieved brutally.

The humorist Will Rogers is said to have observed, “There ain’t nothing that breaks up homes, country and nations like somebody publishing their memoirs.” Mr. Greenspan reportedly was paid an advance of $8 million to publish his. The breakup he causes may be less to his nation than to his reputation.