Of the letters I receive each day, the easiest to handle are the ones that pose questions of fact.

It has been evident ever since Johann Gutenberg invented moveable type that columnists don't know zizz about facts. But some of us are fortunate enough to be backstopped by efficient in-house libraries and librarians, and this permits us to pose as savants.

Not long ago I received a letter signed "Alfred de Quoy." It said, "On 1 January, postal rates for overseas (and South and Central America) were increased. The air mail rate for a 1/2-ounce letter to Europe is now 40 cents.

"The 40-cent stamp has a bust of a man in colonial (?) clothes. The caption is 'Philip Mazzei -- Patriot Remembered.' My Encylopaedia Britannica, my Columbia Encyclopedia, and my American Heritage Dictionary do not list any Mazzei. Who was he? Who remembered him?"

One who is not aided by a team of professional librarians might have trouble with such a question, but 15 minutes after I handed de Quoy's letter to Mark Hannan, our chief librarian, he was back to me with this report:

"Alfred de Quoy, who lives in McLean, is a U.S. Army general. Mazzei was a physician, merchant and horticulturist. He was born in Italy and emigrated to Virginia in 1773, settling a few miles east of Charlottesville, adjoining Monticello. During the Revolution, he was sent to Europe as an agent of the Commonwealth of Virginia to borrow money. If you need more, see page 469 of the Dictionary of American Biography, Volume XII, which we have available for you."

Here is another example: Drew Broach of Gaithersburg wrote to Ben Bradlee, executive editor of The Washington Post, and asked him to explain the origin of the expression "man bites dog." Bradlee lateraled the inquiry to me, but I didn't have the foggiest notion of how to respond to it.

I didn't mind the likelihood that Drew Broach was about to discover my ignorance, but I was dismayed by the prospect that Bradlee would also be privy to this information. Ben Bradlee does not suffer fools gladly.

Fortunately, our library took the Broach/Bradlee inquiry in stride. A few minutes after I left it with librarian Andrew Mayer, he had an answer for me.

John B. Bogart (1845-1921), who was city editor of the New York Sun betweeen 1873 and 1890, devised the classic definition of what is news and what is not. Bogart said, "When a dog bits a man, that is not news, because it happens so often. But if a man bites a dog, that is news."

Bogart's definition of news brings me to Gershon Fishbein's attempt to define history.

Fishbein is the publisher of the Environmental Health Letter. He was intrigued by Rep. Elizabeth Holtzman's comment after she was defeated for a seat in the Senate. Holtzman said she would "miss being able to play a role in history."

This set Fishbein off on a philosophical tack. He asked himself: What the hell is history, anyhow?

"Does history belong only to politicians, or to those in public life?" Gersh wondered. "Is an individual who goes quietly about his business, obeys the law, pays taxes and raises a family considered ineligible for a place in history? Or does history have a larger grasp, taking in not only those who score touchdowns but also those who play their lives between the 40-yard lines? sIt seems to me that history is flawed when it recognizes only those whose names and faces are in the papers every day."

Thank you for those perceptive questions, Gershon.

I have no idea of how they should be answered, and I'm afraid that if I were to submit them to our library, its computer would respond, "No such category. Please consult your directory before dialing again."

How sad! We have taught our computer to retrieve facts, but we have not yet taught it to think. So what good is it?

Even mere humans can retrieve facts, and some of them can also evaluate facts, put them into perspective and form judgments about them. On some assignments, one might actually prefer the help of a mere human to that of a computer.

Columnists, of course, welcome help from any source, living or elecronic. Anybody who doesn't know the origin of "man bites dog" needs all the help he can get.