"Please tell me what's wrong in having a student think?"

With these words of defiance, English teacher Cyril Lang told his principal last June that he would not obey her order to stop teaching two classics by Aristotle and Machiavelli which Montgomery County curriculum officials had decided were too difficult for tenth graders.

But Lang's confrontation with the Montgomery school system, which has now reached the point where he faces a seven-month suspension without pay, raises a series of even more complicated questions. They are being wrestled with by schools around the area and throughout the country, though almost never with the drama that Lang's predicament has caused.

How much freedom should individual teachers have in deciding what to teach?

What powers should principals have in running their schools?

Who should control the schools -- the public and the school boards it elects or the people who teach in them?

And finally, what difference does any of this make in how much students learn?

"It's an old dilemma, an old struggle," said George Weber, a researcher who worked for many years for the Council for Basic Education, a national citizens group that favors higher intellectual standards in schools. "What do you do with a teacher who is particularly tough? The more common problem, of course, is the teacher who doesn't meet minimal standards. But we still have the problem of how tough can you let someone be within the bounds of a uniform public school curriculum."

The answer in Montgomery and other local school systems is that committees of teachers are involved in writing the curriculum and that once it's adopted they all are supposed to follow it. The curricula have objectives that teachers must try to meet, grade by grade, but how much choice they have in the ways to meet them and the books to use varies considerably.

In Montgomery County, for example, there are several hundred books for a high school English teacher to choose from at every grade level, though not Aristotle's "Poetics" and Machiavelli's "The Prince," which Lang used with tenth graders. If teachers want to add a book, they must first get it approved by a system-wide review committee that includes at least five teachers and a supervisor.

The 10th-grade list includes anthologies of short stories, plays and poems as well as full-length works such as Shakespeare's "Julius Caesar," George Orwell's "Animal Farm," J. D. Salinger's "Franny and Zooey" and Dick Gregory's autobiography, "Nigger."

"In a public school system you have to have reasonable procedures to determine what is to be used," said Montgomery Supt. Edward Andrews, who has recommended to the county school board that Lang be suspended. "If each teacher had complete autonomy, you couldn't have a county-wide curriculum and I don't think you could say to taxpayers that you have a school system."

Like Montgomery County, District of Columbia schools have an approved list of textbooks. However, associate superintendent James T. Guines said teachers are free to decide in each school which additional books they wish to use as long as they meet curriculum objectives.

The District's new competency-based curriculum states in detail the goals, teaching activities and tests for all major courses, Guines said. It also contains lists of recommended books, but not required ones.

"We believe in the teacher having some say-so in the materials to be used to get to the objectives," Guines said. "The outcome is the important thing. And we are trying to standardize the outcome, but not the means to the end. That should be left to teacher judgment and teacher creativity. . . . If we tried to standardize everything, how close do we get to the assembly line?"

The area's other two large systems, Prince George's and Fairfax, also have approved book lists. But, unlike Montgomery, Prince George's allows individual schools considerable flexibility in switching the books from grade to grade, and Fairfax has a widely used system of exceptions to let particular teachers use particular books.

However, both of these school systems, like many others around the country, have considerably more uniformity and more restrictions on teacher choice than they did during the widely innovative years of the late 1960s and early 1970s. The changes were made by school board resolutions that themselves were a response to public pressure.

"The public now wants the assurance that the program is consistent, that the program is coherent, that the program is sequential," said Donald G. Kauffman, supervisor of English in Prince George's County schools. "The only way to do that is to have a formalized structure and stick with it."

Dennis Gray, associate director of the Council for Basic Education, said his group favors having a strong basic curriculum in the schools, rather than a proliferation of electives. But he added:

"There certainly are teachers in every school who are better than the curriculum, who have an unusual ability to make difficult material accessible to younger students, and there's real trouble when the school isn't able to let them fly. . . . When the view comes out that the system is more important than the people in the system, when the system must be preserved at some human expense, that's really dismaying."

"Throughout the country there's a reaction now against the 'anything goes' curriculum of the 1960s and early '70s," said Fenwick W. English, a former school administrator who now directs the education audit division of Peat Marwick and Mitchell, an accounting and consulting firm. "They weren't teaching fundamental skills and achievement declined. The result was that we were graduating students who were functional illiterates and we still are.

"When you have a strong curriculum," English continued, "you have to know that the kids in Algebra 2 have learned certain things in Algebra 1. The same thing is true in English. You have to look at the whole sequence of things, not just what one teacher is doing."

English said another issue involved in Lang's case is his defiance of a direct order from his principal, Anita Willens.

"No matter what the subject is, does the principal have any real authority?" English said. "Certainly, the principals are being held accountable for how well their schools do, but if they can't issue a simple order, how can they be? No state says a teacher can do whatever he wants as long as he thinks it's right. The teaching certificate is issued by the state with the obligation to adhere to its laws and authorities."

Lang contends that even though Montgomery school officials say they are committed to a uniform curriculum, in fact the curriculum guides are not followed consistently. Despite the grade-by-grade lists of approved books, Richard Crowley, the county's English coordinator, confirmed that high school teachers often use books slotted for lower grade levels with students whose achievement is poor.

"Listen, I wasn't naive," said the 55-year-old Lang, a bearded, burly widower with four grown children. "I knew [defying authority] might be scholastic suicide. But there were rights at stake here, and I had to take the gauntlet and go with it."