Alan Greenspan has returned to the private sector as an orbiting spacecraft re-enters the Earth’s atmosphere. In a fiery glow, the just-departed chairman of the Federal Reserve Board earned a reported $250,000 for giving a talk to the picked clients of Lehman Brothers. Now he’s said to be dickering over the price of his unwritten memoirs. It seems the maestro who commanded interest rates by the battalion has been reduced by the publishing industry to but another celebrity without a manuscript.

The immediate problem is the structure of the book business. It is a free market. Nothing the former chairman did in the interest-rate line could prepare him for the force of this fact. Examine that dollar bill in your wallet. On it is written the legend, “This note is legal tender for all debts, public and private.” The money that Mr. Greenspan printed, you had to accept. The law said so. But no law says you have to buy his book. Here, incidentally, is the problem with literature as a job of work. Book writing would be a steadier and more lucrative calling if the customers had to take what the publishers printed. Sadly – we speak now for the nation’s writers and poets – there is no such compulsion.

Certainly, a Greenspan memoir could sell. With just a little authorial candor, it could sell millions. Readers of Mr. Greenspan’s not always scintillating prose may have their doubts about the best-seller list. But what his story admittedly would lack in, let us say, narrative power, it could more than make up for in irony. The question is whether Mr. Greenspan can muster the artist’s courage to tell the true story of his remarkable intellectual odyssey.

Compare the professional starting and ending points of the nation’s former top financial brain. As a Wall Street economist in the 1960s, he worshipped at the hem of Ayn Rand, author of “Atlas Shrugged” and founder of the creed known as Objectivism. He was a gold-standard man to the bone. “In the absence of the gold standard,” he wrote in 1966, “there is no way to protect savings from confiscation through inflation. There is no safe store of value. If there were, the government would have to make its holding illegal….”

In 1987, a man also by the name of Alan Greenspan – a fellow who looked remarkably like that younger man’s father – landed a job as the nation’s top administrator of the pure paper dollar. Through what process of reasoning did the forty something Objectivist become the sixty something central banker? It is not so farfetched to imagine Mr. Greenspan replying to this soul-baring question on Oprah’s couch. But would he deliver the goods?

At least, in the Maestro, Oprah would have found an honest author. Mr. Greenspan’s personal integrity is above question. It is almost too beyond imagining. The former steward of the U.S. money stock, fine-tuner of its interest rates and No. 1 intervener in the world’s financial markets retired worth a few miserable million dollars. No more. Consider the temptations. Martin Mayer, in his book “The Fed,” relates how, in 1998, a reduction of just one quarter of one percentage point in the federal funds rate (the rate that Mr. Greenspan personally pushed around) caused the stock market to soar by more than 7% in just 60 minutes: “Roughly $1 trillion was added to the world’s wealth, on one man’s say-so.” It is a credit to the United States that its chief central banker could retire no richer than the average 2006 entry-level investment banker.

Yesterday came news that the same Washington lawyer who negotiated the Clintons’ high-priced book deals has agreed to represent Mr. Greenspan. If his advance matched the former president’s, it would total $12 million. But the suddenly enriched author would be under an obligation. He would be expected to explain, among other things, how an apostle of pure laissez-faire could be led to accept a job cranking the U.S. monetary printing press. We suspect we’re not the only one eager to know. Write fast, Maestro, or, as one long ago editor once told us, “turn the crank.”