What little has been written about the decision by a number of American book publishers to stop selling to South Africa has focused primarily on its impact in that country. Apartheid-free American texts and children's books are in much shorter supply there now. And at the University of Cape Town Medical School, where 80 percent of the patients are black, the most recent American medical books and journals are no longer available.

Suppression of information and ideas, however, can have a boomerang effect. The American publishers engaged in this banning of information are motivated by fear of losing sales to those American municipalities that require that any company doing business with them sign an affidavit assuring that it will no longer have anything to do with South Africa.

In Houston, with its large, heavily used public library system, an ordinance was passed by the city council last July requiring that such affidavits be obtained by all city agencies. The director of the library, David Henington, is an intense opponent of apartheid, and he is an intense believer that people who use his library are entitled to free access to ideas and information. Both those goals appear to be on a collision course once restrictions were placed on the companies from which the library could purchase materials.

"We couldn't get The Wall Street Journal anymore," Henington told me. "They refused to sign the affidavit because they have subscribers in South Africa and they also have a correspondent there." Also prohibited were new supplements to the "Readers Guide to Periodical Literature," an essential library resource. It's put out by H. W. Wilson, a company that also refused to sign the affidavit. The firm also publishes "Current Biography" and other basic research tools.

Henington was especially saddened to have to stop doing business with Encyclopedia Britannica, being dismayed to see the library bereft of new films by that firm. "Not having them," he says, "is a great hardship. They're fantastic, especially in the arts and sciences."

Another supplier who stopped supplying the library was a national black Methodist church organization. "We buy a directory from them every year, but they couldn't sign the affidavit because they are 'in contact' with South Africa. That contact consists of providing food and clothing to people in need there."

Henington decided to do some quiet lobbying to make just one exception to the anti-apartheid resolution: for information. For further illustration, he wanted to reinstitute the library's subscription to two newspapers in South Africa. "They were windows into that country."

It took him months to convince the members of the city council that the restrictions on the public libraries were limiting the freedom of access to information of the very constituents of the members of the council.

Finally, in October of last year, the Houston City Council passed an ordinance exempting "publications, where the public official responsible for the procurement certifies in writing that such procurements are necessary to provide adequate levels of service to the public."

Five months earlier, at the American Library Association annual conference in San Francisco, some anti-apartheid ALA members, who are also passionate about the First Amendment, offered a resolution to support public library directors, such as Henington, around the country.

During floor debate, the resolution was attacked as "racist." There was an open standing vote, and those ALA members supporting free access to ideas were hissed by some of their opponents. The resolution was thumpingly defeated.

The American Library Association has been consistently and effectively opposed to censorship in the United States. But in San Francisco, a majority of the membership voted for the banning of books -- not only in South Africa but also in their own libraries.

In the minority was the indomitable Judith Krug, director of the ALA's Office for Intellectual Freedom. For years she has been an invaluable resource for librarians under siege throughout the country. After the First Amendment was trounced in San Francisco, Judy Krug said to me, "How can anyone involved with libraries go on record and say, 'We are going to solve problems by withholding information?'"

But it's in a good cause.