BATTLE CREEK, Mich. (AP) _ The marketing skills of Will Keith Kellogg put cold cereal on the world's breakfast tables, but the ''king of corn flakes'' worked as hard at giving away his fortune as making it.

In the 58 years since the late Kellogg Co. founder established the W.K. Kellogg Foundation, it has dished out more than $1 billion on programs to overcome the problems of hunger, disease and ignorance - both at home and abroad.

''There's nothing glamorous or sexy about a grant to a land grant college to extend knowledge to farmers in a poor, rural setting,'' Kellogg Foundation board member Dorothy Johnson said.

''The Kellogg Foundation is not out tooting its horn to toot its own horn,'' said Johnson, who joined Kellogg's board six years ago.

The foundation's $3.58 billion in assets is exceeded only by the Ford Foundation and the J. Paul Getty Trust. Kellogg gave out $89 million in the year ending Aug. 31 and plans to donate more than $110 million this fiscal year.

Despite its size, the Kellogg Foundation keeps a remarkably low profile.

''A number of the major foundations seem better than they are, and they devote considerable effort to maintaining that appearance,'' Waldemar Nielsen wrote in his book ''The Golden Donors.''

''Kellogg is the reverse case: It is substantially better than it is generally seen to be,'' Nielsen said in the book.

The relative obscurity of the nation's third-largest foundation, those familiar with it say, has its origins in the mission set by its creator - applying existing knowledge to the problems of people.

Still, the foundation is leaving a lasting mark around the world as it strives to bridge the gap between what is known and what is practiced.

Among its major accomplishments:

-Training thousands of Latin American nurses, doctors, dentists and hospital administrators, first through a fellowship program created during World War II to bring health professionals to this country and later through aid in creating and building medical and nursing schools in the region.

-Nurturing the development of community colleges in the United States and helping them grow into one of the nation's leading sources of post-high school education.

-Fostering the growth of agricultural extension services at land grant universities around the country so farmers could benefit from the results of agricultural research.

But more than anything else, the Kellogg Foundation has focused its attention on improving the lives of children.

''Mr. Kellogg was very, very much interested in youth,'' said Jack Mawdsley, former superintendent of the Battle Creek Public Schools and now a programming director for the foundation.

Kellogg's interest in improving the lives of children grew out of his own experience, according to Nielsen. The founder had poor relations with his son, John L. Kellogg, who quit the company his father hoped to turn over to him, and with his grandson, John L. Kellogg Jr., who did the same.

Both son and grandson predeceased him, as did two wives. Kellogg also endured numerous health problems, including glaucoma-induced blindness, though he lived to 91. He died in 1951.

Kellogg's charitable interests may have been influenced by ''the many tragedies in his life ... and his deep personal sense of loneliness,'' Nielsen wrote.

What makes the Kellogg Foundation stand out from its peers, observers say, has been its clear statement of goals and systematic pursuit of ways to fulfill them.

''Compared to the egocentricity, ulterior purposes, lack of a genuine sense of direction and general organizational ineptitude of more than a few donors, Will Kellogg was a giant: compassionate, broad-minded, clearheaded and with great practical wisdom,'' Nielsen said.

For most of its first decade, the foundation concentrated its efforts in a seven-county area near Battle Creek, home of the foundation and cereal company. There, it financed the Michigan Community Health Project, which set up a network of health clinics, community hospitals and medical screening programs.

As the United States entered World War II, the foundation, at the urging of the federal government, expanded its horizons to Latin America, where it began offering fellowships for health professionals to study in this country.

After the war, the foundation began making grants around the world.

As it has from the beginning, the foundation stresses applications of knowledge to social problems, rather than learning for its own sake.

''Our central theme is action, taking the best of what's known from various disciplines ... to tackle significant societal concerns,'' said Russell Mawby, chairman and chief executive officer.

Because the foundation is the largest single stockholder in Kellogg Co., Mawby sits on the cereal maker's board of directors. Federal law forced the foundation to divest itself of what once was a majority of Kellogg stock, but it still holds a 35 percent stake.

The foundation and company have no other formal ties, but Kellogg Co.'s strong market position - 43 percent of worldwide sales of breakfast cereal - is the principal source of the foundation's rapid growth, which nearly has tripled from $1.2 billion in total assets in 1984.

As the foundation has tried to deal with problems of health, nutrition and education, its staff and board increasingly has reached the conclusion that no single profession or agency has the expertise or resources to solve them.

''The problems of people's lives exist in a community context,'' said Dan E. Moore, an agricultural economist and foundation program director for Latin America.

Integrated rural development programs, as he calls them, try to meet the combined health, educational and agricultural needs of rural Latin American villages by setting up community centers that include health clinics, schools and farmers' markets.

To make the most of its resources, the foundation strives to make grants that will have a multiplier effect. A foundation grant in one Latin American region often spurs national and local officials to direct resources to the area as well, and a program's success leads other communities to emulate it, he said.

The foundation recently has undertaken several projects that are taking it beyond the role of awarding grants and making it a catalyst for change. Its Youth Initiatives Program, for example, has set up panels of young people and adults in parts of Michigan to discuss youth problems and fashion remedies.

The foundation believes resources to overcome such problems as poor education, lack of jobs, drug abuse, pregnancy and violence already are available if courts, schools, police and community groups start talking and working with each other.

''We're not going in there with a pre-set idea of, 'Here's what you need, folks,''' Mawdsley said. ''We want them to identify the problems. ... We want them to write the prescription to their own program.''