Some months after she wrote a magazine article in 1974 about an 84-year-old widow in Philadelphia who had no food, Loretta Schwartz-Nobel returned to the starving woman's home with a bag of groceries. She knocked at the door. No answer. She kept knocking. Finally, a neighbor, overhearing, appeared. "I'm sorry, lady, but you're too late," she told the writer. "They carried her out of here last week. If I'd known she needed food I would have brought her something, I really would . . . She never asked me for any help. She just starved to death right in her bed."

If she were more the cool-pro journalist -- polished in the ways of objectivity, skilled in distancing her emotions from the cruelties being reported, detached from anger about institutionalized violence -- Schwartz-Nobel would have promptly seen that she was getting "carried away." What's this about taking food to the poor? The next thing, she'll become a nuisance in the newsroom for pestering editors that a major story -- starvation in America -- is out there and most of the media are missing it, and missing it big. Perhaps, also, instead of merely blaming others for their inattention, she will decide to throw herself into the story as fully as possible.

That's exactly the course of action she took. It was a moral victory for her and a professional victory for American journalism.

The power of Schwartz-Nobel's books places her in select company with "Let Them Eat Promises" by Nick Kotz, "Rich Christians In An Age of Hunger" by Ronald Sider and "Hunger For Justice: The Politics of Food and Faith" by Jack Nelson.

Since 1974, Schwartz-Nobel has traveled around the country on the hunger beat. She sought out the hungry, public officials running the food programs, farmers, politicians and corporate executives of food companies. She refused to accept the prevailing belief that America had solved the "problem" of hunger. If that were true, she wondered, why did the 84-year-old woman die?

The first person to whom she asked this unsettling question was herself. "I did not know that everyone involved would assume, as I had assumed, that someone else was taking care of her," she answered. For seven years, Schwartz-Nobel looked at the assumptions -- hers and ours -- and the policies of the government.

In Boston, she talked with a food-stamps official who knows of countless people who have no food yet don't meet the program's requirements. In Philadelphia, a social worker reported, "many people think that when you are a senior citizen you get a lot of extras like hot, home-delivered meals, but when you actually try to get them you are told that there are 376 people ahead of you. You have to wait until they die." In Mississippi, she met a physician who spoke of "extreme malnutrition," even kwashiorkor, among black families in parts of the Delta. "Everybody wants to say there is no poverty, no hunger in the United States," the doctor said, "that if a child is hungry, it's the mother's fault. They are crazy."

Everywhere Schwartz-Nobel traveled, she saw connections between the suffering of hunger and the policies that help sustain it. Crop yields are lowered when soil is allowed to blow off the land. Large and all-but-unaccountable corporations are buying out energy-efficient small farms. The meat lobby exerts pressure to keep protein-rich soy products going to animal feed lots, not to the tables of hungry human beings who need it. In the 1970s, Schwartz-Nobel writes, "The country seemed to be running out of everything at once -- energy sources, topsoil, crop land, and food reserves -- while inflation and demand for these resources continued to increase. By 1980 the situation had grown even worse. The individual shortages and failures actually foreshadowed problems that had been building for years. The general public had remained largely unaware that the ground was shifting beneath it because the policy-makers had continued to cover shortage after reported shortage with short-term solutions, gimmicks and unrealistic promises."

It's no minor scrape we're in, Schwartz-Nobel is correctly saying. The Reagan administration -- whose food officials like John Block and Richard Lyng almost create a yearning for Earl Butz, the ex-convict -- has done nothing even to alert Americans that hunger is spreading. In fact, it may be creating hunger, if its plan to give school children less food at higher prices comes to pass. Martin Anderson, a Reagan adviser, is quoted by Schwartz-Nobel as saying in 1980 that poverty had been "virtually wiped out in the United States, our systems of government aid had been a brilliant success . . . They should now be dismantled."

With that thinking now running wild, and few voices raised to stop it, the publication of "Starvation in the Shadow of Plenty" couldn't be better timed. Any one of its pages contains more integrity and intelligence than entire books like "Wealth and Poverty," which is currently being fawned over by the administration. Schwartz-Nobel spent seven years investigating the nation's poverty; by its policies, the Reagan administration doesn't appear to have given the task seven minutes.