Until they learned to read and write: * The owner of a small tire repair business in Tunis relied on memory for all record keeping.
* Mary, an American gypsy of Romanian extraction, kept her four illiterate children out of school in Alexandria, Va., because she was too embarrassed to admit she could not spell or write even her first name.
* Members of a poultry cooperative high in the mountains of central Ecuador were unable to fill out the contracts for their eggs to be transported down the mountainside and sold in Quito.
* The workers in a carpenter's shop in the tiny West African state of Gambia had to rely on the only man in the shop who could read and write to make precise measurements. Nobody else could read the tape measure.
What these illustrations show is the crucial importance of literacy - in terms of greater self-esteem, of higher wages, and of participation in society - in a world where 1 out of every 3 adults is illiterate.
Perhaps most important, in many third-world countries there is an urgent awareness that literacy is the path to development.
Even in the midst of world economic stagnation, which has resulted in an actual decline of living standards over the last decade for some third-world countries, literacy stands out as one of the brighter beacons of hope.
While many cherished development projects have been pruned back to the most meager levels, the commitment to education and literacy remains as strong as ever. In some cases, particularly in Africa, levels of spending have not only been maintained, but have even been increased through this year.
There is also a new and more compelling need for literacy in the developing world: As the developed world becomes increasingly more computerized, a largely illiterate work force in the third world will be less able to absorb and catch up with the new technology.
Figures from the United Nations, the World Bank, and World Military and Social Expenditures 1982 show that while, admittedly, arms outlays sometimes exceed educational expenditures in some third-world nations, public spending for education in poor countries increased nearly 700 percent - from $7.8 billion to primary-school children to read and write, although adult literacy programs have also been stressed.
In some countries, such as Cuba and Nicaragua, mass literacy campaigns do more than just enable more people to read and write. Literacy programs have become government tools to instruct citizens how to follow political directions.
The emphasis given to literacy, and education in general, is borne out particularly in Africa. In Tanzania, primary-school enrollment quadrupled between 1960 and 1979; in Mozambique and Nigeria it doubled. The Ivory Coast and Botswana spend a greater percentage of their gross national product on education than either the United States or France.
The results have been encouraging.
According to the World Bank Development Report for 1982, the literacy rate in the developing world stood at only 33 percent in 1950. But it rose to 38 percent in 1960, 46 percent in 1970, and 56 percent in 1979. Some development specialists are wary of the validity of those figures because they suspect that sometimes countries list what they project the literacy level will be rather than what it actually is. Perhaps a more convincing yardstick is the increasing literacy that development experts discover every time they return to their regions.
John Ryan, a promoter of literacy and training programs for UNESCO (United Nations Educational, Scientific, and Cultural Organization) in Paris, explains the third world's commitment to literacy:
''I think they see literacy as instrumental to all the tasks of national development. Unless you have communication with the population at a certain level of sophistication, you can't do very much.''
Mr. Ryan has just returned from Gambia, one of about 30 countries in sub-Saharan Africa that requested UNESCO at a meeting of education and development ministers last year in Harare, Zimbabwe, to explore ways to wipe out illiteracy in Africa by the year 2000. The proposal goes before UNESCO's annual conference in Paris this fall.
A number of African countries - among them Tanzania, Kenya, Ethiopia, Botswana, Nigeria, and Senegal - are pursuing mass literacy campaigns. But the proposed UNESCO project, if it comes to fruition, would mark the first time a campaign in Africa has been conducted on a comprehensive regional basis.
Yet among education and development specialists, there is no reason for complacency. While the rate of illiteracy is going down, the absolute numbers continue to go up because world population continues to increase.
There are now some 800 million illiterates in the world. The expectation is that this figure will reach 950 million or 1 billion by the year 2000. In some 20 countries, more than 80 percent of the population is illiterate.
According to the International Reading Association, based in Newark, Del., the Arab world has the greatest proportion of illiterates: about 62 percent of the population. The rate is about 60 percent in Africa, 37 percent in Asia, and 20 percent in Latin America. In terms of actual numbers, more than half - 599 million - are in Asia.
The problem is even more acute for women. Women constitute an ever growing proportion of world illiterates, at just over 60 percent. This reflects on the status of women in some third-world countries.
For the illiterate, the world is fraught with frustration and obstacles.
An 18-year-old New Yorker dreaded using the subway because he couldn't read the names of the stations. Millions of illiterate mothers in India don't even realize they put their children's health at risk when they cannot follow simple instructions on a can of food. Ghanaian farmers sense, but are not always sure, they are being cheated because they cannot read the scales when their produce is being weighed. A businessman in the Middle East is unable to secure credit because he is unable to keep records.
Education experts have observed, too, that illiterates go to elaborate lengths to conceal their illiteracy.
Illiteracy has become part of the syndrome of underdevelop-ment. Any socioeconomic map of the world reveals a close correlation between illiteracy and poverty, poor health, high infant mortality, low life expectancy, and population growth.
Conversely, in Kerala (south India), Sri Lanka, Thailand, and South Korea, sharply reduced population growth and infant mortality rates have been linked to higher educational achievement.
As one UN expert put it: ''Women who are better educated want and have fewer children and can provide their families with better nutrition.''
Development specialists even go so far as to say that literacy is almost as important as food and clothes, because without literacy it is hard to get food and clothes.
Says George Psacharopoulos, an education research adviser at the World Bank: ''The global proposition that spending on education is an investment with a high social rate of return is well supported by the accumulated evidence over the last decade.''
A recent World Bank survey also shows that, all things being equal, average farm productivity increases by 7.4 percent when a farmer has completed four years of elementary education. The social dangers of inadequately educating a society are clearly demonstrated in crime figures. It is a phenomenon not restricted to the third world.
In a speech recently, Barbara Bush, who heads a national campaign against illiteracy and is the wife of the US vice-president, reported that the US spends percent of the prison population. Some 85 percent of juvenile delinquents who end up in American courts are functional illiterates.
The 1982 UNESCO Statistical Yearbook puts the US illiteracy rate at a very low 1.1 percent, but many US educators are concerned about the high incidence of functional illiteracy, which includes the inability to read a product label properly in a supermarket. A large influx of less skilled people into the United States is held responsible for the US dropping since the 1950s from the 18th most literate member of the UN to 49th of the 156 member states.
For third-world citizens the challenges of illiteracy can seem almost insurmountable. Among them:
* Multiplicity of languages, especially in Africa. Nigeria has more than 100 languages. Hard political choices have to be made on what languages will be chosen for teaching purposes since costs prevent mass literacy campaigns from being conducted in all languages of a country.
* Entrenched oligarchies - Latin America is cited - for which it is not in the interest of the elite to have an articulate, well-informed public.
* Uneducated parents reluctant to have their children go to school for fear they will lose their traditional hold over them.
* Expanding literacy skills in countries that do not have a large enough economic base to satisfy those skills. Development analysts concede that in these circumstances literacy can sometimes compound rather than ease political frustrations. To this end, international agencies such as UNESCO are now doing more to gear literacy programs to be of greater relevance to the areas in which people live.
* Rural areas where there is a scarcity of written materials such as newspapers, commercial signs, and flyers. One of the controversial aspects of mass literacy campaigns is that there is frequently no follow-up; in a culturally deprived atmosphere new literates in time lapse back into illiteracy.
A major criticism of UNESCO's international literacy campaign in the 1970s was its inability to maintain literacy among new literates. Some education experts put the dropout rate in some rural areas of the world as high as 90 percent. Literacy campaigns today recognize the need for much greater follow-through so that new materials can be supplied to consolidate what has already been learned.
In these instances, the literacy message going out is not simply ''learn to read'' but ''read so you can read more.''
Lowest third world illiteracy rates:
Carribbean countries (Barbados lowest with 0.7%) Philippines 17.4% Mauritius 21.0% Sri Lanka 22.4% Tanzania 26.5% Zimbabwe 31.2% Countries exceding 90% illiteracy:
Mali Niger Upper Volta Sierra Leone Chad Somalia Senegal North Yemen Guinea Bhutan