Some years ago, a junior high school librarian in downstate Illinois taught me a lesson. One of my books for young readers, she told me, was being shunned by some of the parents, and she thought I should understand why. (The book was not part of the curriculum; it was in the library for optional reading.)

My novel included a couple of mild expletives, "damn" and "hell." The librarian said the objections were from Christian fundamentalists who take "damn" and" hell" literally. They will not allow their children to be exposed to blasphemy.

"It's too simple," the librarian said, "to just yell 'Censorship!' You have to know where these people are coming from."

I've been thinking of those people as I followed the oral arguments in the widely publicized Tennessee case brought by parents objecting to what their children had to read in a public school. These were not optional library books. At issue is a series of Holt, Rinehart and Winston textbooks used in the second through eighth grades to teach reading.

The case, Mozert v. Hawkins City Public Schools, involves seven families who insist that the texts violate their religious beliefs. In "The Diary of Anne Frank" and other fiction and nonfiction works excerpted in the series, they find evocations of secular humanism, witchcraft and other baleful influences that can damage the souls of their children.

It's easy enough to make fun of the examples shown by the parents to the press and in court, but having met a number of such conscientious objectors to what is taught in public schools, I can attest to how deeply honest their beliefs are.

After the trial, the federal district judge, Thomas G. Hull, came up with a ruling last October that the kids involved did not have to attend reading classes when the texts collided with their religious beliefs. Instead, they would have to go home and be taught reading skills there.

Recently, in Cincinnati, three judges from the Sixth U.S. Circuit Court of Appeals reviewed the case. Timothy Dyk, lead counsel for the school board, claims there are two basic issues. Is it true, as the parents charge, that their First Amendment right to free exercise of religion is undermined by the state's insistence that their kids read these textbooks? The other issue is whether there is "a compelling state interest that is thwarted by allowing these religious objectors to be taught at home."

Michael Farris, the attorney for the parents, and himself a fundamentalist Christian, pressed the free-exercise-of-religion argument. Dyk, trying to show a compelling state interest in keeping the kids in school alongside their classmates, pointed out that the mandatory reading of these textbooks is part of an integrated curriculum. The students might come across evolution in one of the readings and that would lead to a more extended treatment of the subject in science class. Accordingly, students who went home to study reading would lag behind the other kids in other subjects.

In a telling point, Dyk said: "The plaintiffs want to teach their children about moral absolutes. . . . If you want to come to the public schools, you must learn the core curriculum, which includes critical thinking. . . . We are setting up public schools to teach students, as a civil matter, things that will make them good citizens. If you don't take the core part of the benefit, you're not doing what we're spending the money for."

Eventually, the teaching of critical thinking will be diminished for all the kids in the school. As the National Law Journal reported, Dyk "warned that if the District Court's decision were upheld, many similar suits would be brought nationwide and textbooks would be 'watered down' to avoid litigation." The Cowardly Lion in the "Wizard of Oz" might well have been modeled after members of school boards and publishers of textbooks.

Whatever happens in the Sixth Circuit, the case will surely be appealed to the Supreme Court. Should the parents lose there, have they no constitutional options left? Indeed they have, and some have already exercised such an option. In 1925, the Supreme Court in Pierce v. Society of Sisters, overturned an Oregon statute that required children to attend only public schools. Said the court:

"The child is not the mere creature of the state; those who nurture him and direct his destiny have the right, coupled with the high duty, to . . . prepare him for additional obligations." They can enroll the child in a private, religious school where the parents can exercise their First Amendment religious rights without impeding the rights of public-school parents to nurture their children the way they want to.