DEAR Moon, Neil, Charlie and Bill:

Congratulations. At any given moment only .000000005 percent of the population can be a Cabinet secretary, and you four are in this elite lineage tracing back to Alexander Hamilton. The reasons to accept such a line of work are surely compelling -- the legal authority, the president's ear, not to mention an office the size of a tennis court and the right to be called Mr. Secretary for the rest of your natural life.

Compelling, but not enduring. Today you may be a political Ozymandias, but tomorrow the slightest breeze may erase your footprints in the sands of political life. Quick, can you tell me who Lewis Schwellenbach, Frederick Seaton and John Gronouski were? All Cabinet secretaries under, respectively, Truman, Eisenhower and Johnson. William Rogers can appear on an American Express ad and ask, "Do you know who I am?" Henry Kissinger cannot. And appreciate that Thomas Kleppe and Harold Ickes held the same position as interior secretary -- with grossly different results.

If you want to leave something behind other than your official portrait, you might want to consider the following 10 unsolicited suggestions on how you can make a difference and leave a legacy. Accept them in the spirit of police commissioner Theodore Roosevelt -- who in 1895 would personally swoop down on the streets of New York to monitor the performance of his cops. 1. Get first-hand experience. Secretaries feel chained to their offices, where there is always another call to be returned or function to attend. But Washington is not America. Carter is right. Unless a secretary gets out of D.C. and into the field, he will become an expert in Nicholas Murray Butler's definition -- someone who knows more and more about less and less.

The goal is for the policy-maker to experience the community he is affecting, rather than to "experience" it derivatively through four levels of memoranda. So if you're the transportation secretary, drive all night on a truck rig; the attorney general could benefit from a day in a cruising squad car; the secretary of HUD might want to stay in a federally subsidized housing project; a labor secretary could work in some of the hazardous work sites his department's OSHA is attempting to make more safe. 2. Develop a theme. Take a stand at the start. People remember grand themes, not 10-point programs. Give credit to Earl Butz, who doggedly and skillfully pushed for a nonsubsidized free market in agriculture, and Griffin Bell, who sought to continue the post-Watergate depoliticization of the Justice Department. "To paraphrase the trial lawyer's opening statement to a jury, Judge Bell 'told people what he was going to do, he did it, and then he told people he did it,'" according to Ray Calamaro, who was a top Bell aide at Justice. "As a result, he could refer to this higher value as justification for not doing inconsistent things of lesser value."

Of course, some themes can be memorable clinkers -- say, 'Dulles' "brinkmanship." But without a theme you will be seen either as a technician or as Churchill's description of pudding. 3. Reach into, and motivate, the bureaucracy. It's easy to allow your personal staff to become a moat between you and your agency. But efficiency is not necessarily effectiveness. All those GS 13s gas your vehicle. Without them, you stall. Acknowledging the value and mission of career people can motivate them to produce rather than coast. When Vice President Mondale swore in John Shenefield as head of Justice's Antitrust Division, Shenefield immediately lauded two career litigating attorneys, who had accompanied him to the White House for the ceremony, as representing the heart of his agency. President Kennedy once directly called a startled antitrust division lawyer on a matter he was handling. It probably took about 21 minutes for the work of the Kennedy call to spread throughout that agency. Presumably many division lawyers for a time thereafter tingled slightly when their phones rang. 4. Develop a constituency . Ostensibly a secretary has a constituency of one -- the president of the United States, at whose pleasure he serves. But unless the Cabinet official cultivates a supportive constituency, he will lack the roots to survive the first gusts of criticism or controversy. That is why blunt-talking Earl Butz and Andy Young lasted even as long as they did -- and why FBI Director J. Edgar Hoover and master-builder Robert Moses survived decades. Their public images as doers and dragon-slayers gave them a latitude and longevity to develop their programs.

More current examples also indicate the potential. Stanley Sporkin, the head of enforcement at the Scurities and Exchange Commission, and Joan Claybrook who runs the federal auto safety program, have such public notoriety and popularity as champions of consumers against business that superiors would think twice before canning them for any aggressive action. 5. Nurture Congress -- to a point . You will be judged in large measure on how well you do in Congress -- which in turn depends on a) whether you get along with your key committee chairmen and b) whether you can find skillful congressional champions for your causes. You may not succeed with a) and b), but you'll surely fail without them. "Ray's up here all the time," reports one counsel on the House Educaiton and Labor Committee of Labor Secretary Ray Marshall. "Rep. Perkins [chairman of the committee] and Rep. Thompson [chairman of the labor subcommittee] love him. They think he's a superb secretary."

Which is great for Marshall -- but at what what cost?With 300 congressional committees vying for influence, a secretary may be required to appear at hearings several times a day or a dozen times a month. Excessive ceremonial appearances before Congress steal time from other activities. Conclusion: Be forthcoming and friendly with chairman and champions, but establish early a policy of limiting congressional appearances to no more than, say, two a week or five a month. 6. Talk to your critics . . . but have your press office answer them . It serves no purpose to convert occasional opponents into implacable enemies. James Schlesinger periodically referred to environmentalists and nuclear power opponents as "the kind of people who supported Ho Chi Minh." Griffin Bell talked to and charmed most of the 22 senators who voted against his nomination. Partly as a result, Schesinger left office to a Bronx cheer and Bell to kudos.

Though Henry Ford says he lives by the credo "never compalin, never explain," an attack unrebutted is an attack repeated. A critic will naturally assume that your silence implies corroboration, or at least acquiescence. So whenever New York Times columnist William Safire would write anything incorrect about Bell or the Justice Department, Terry Adamson, the head of public affairs for the department, would immediately and directly call Safire to correct him. Once put on notice, it's hard for critics to recycle errors. 7. Work nights, even weekends. Since your responsibilities are as great as your term may be brief -- the average secretary in this century lasts about two years -- you might as well give it your best shot. Joe Califano was fired despite, not because, of the fact that he was one of the alltime workhorses.

One would think this injunction to work hard is self-evident, but it is often observed in the breach. Attorney General William Saxbe used to try to leave at 4:30 to play golf, which is why perhaps one American in 100,000 can recall that he was ever attorney general. 8. Write at least some of your own speeches. I realize this exhortation borders on the naive in contemporary officialdom, but there is modern-day precedent to this quaint notion. Attorney General Ramsey Clark would write his own speeches because, as he later said, "either the bureaucracy was going to control me or I was going to try to direct it." The benefits are many. You remember things better; your delivery is more natural; and your staff, if not the press, come to regard you as a thinker, not merely a thespian. 9. Think about the victims . Business lobbies utilize law firms, trade groups, national advertisements to rail against "big government regulation." The elderly who suffer from ineffective and overpriced drugs, for example, lack such megaphones. It is right and popular for you to be a tribune for the victims.

Neil Goldschmidt got off to a good start here by telling one "Meet the Press" questioner that he would not cut back on auto safety programs because "it is very hard to tell somebody who has turned into a paraplegic or epileptic because of an automobile accident . . . that there isn't any reason for the government to pay attention to safety standards." 10. Have a place to go back to . If you're too scared of being sacked, you'll play it too safe. So have a safe harbor to retire to the day after or the month after you leave. Anticipate the worst so you can do your best. That Alfred Kahn knows he is a phone call away from teaching again at Cornell partly explain a candor his colleagues envy.

If you follow this advice, your terms might be brief -- loyalty rather than controversy seems to be this administration's barometer of the good secretary -- but they won't be dull. And there will be the chance that you can return to New Orleans, Portland, Coca-Cola and Textron with a legacy rather than a title-for-life.