Even after teaching English to high school students for most of 20 years, Cyril Lang says he has "never lost the thrill."

"A kid is pondering something and pondering something -- and then there's that moment of illumination," Lang explains. "It's extraordinary to be part of something like that."

But when Lang talks about teachers and school administrators, his voice turns hard and angry.

"They treat us like second-class citizens," he says. "Second class. And they make us do what they want . . . even though they don't follow many of their damn rules themselves . . . Well, I'm not second class. I want respect. I won't let them always do it to me. They have to make room for teachers, but they're afraid: We might shove some of their damn rules down their throats."

Then Cy Lang smiles and laughs quietly, his face reddening above a well-trimmed beard. "Do I come on too strong?" he asks.

Last week Lang, who is a 10th-grade English teacher at Charles W. Woodward High School in Rockville, drew wide attention when he was threatened with a long suspension without pay for refusing to stop teaching two classics, one each by Aristotle and Machiavelli. Montgomery County curriculum officials had decided that the works were too difficult for 10th graders. Lang's principal, Anita Willens, had ordered him repeatedly to stop using them.

Lang persisted. But his claim that teachers have the academic freedom to add unapproved books to the countywide curriculum was rejected by Supt. Edward Andrews who charged Lang with insubordination and recommended to the school board that the teacher be suspended without pay for seven months. The penalty would cost Lang almost $17,000 in lost salary.

It was not Lang's first conflict with authority in the Montgomery County school system, but it was by far the most dramatic.

"He's a gutsy guy. He's smart and he's charming," one fellow teacher said about Lang, "but it seems no matter where he goes, there's a great deal of controversy . . . There are certain times, you know, that the sharks are out and you walk a different path. But Cy, he goes right in there and does it."

At age 55, Lang is a bearded and burly widower with four children. Only the youngest -- a 15-year-old daughter -- still lives at home, which for the past three months has been a fourth-floor apartment near Aspen Hill. There is a set of barbells and weights on the kitchen floor, an exercise bike in the hallway and hundreds of books on shelves and in closets.

Before Lang started teaching in Montgomery County in 1970, he was a teacher and encyclopedia salesman in his native New Jersey. He was born and raised in Newark, and later taught in the suburbs. He majored in drama at Lafayette College, where he earned a bachelor's degree, and at the University of North Carolina, where he received a master's.

For several years Lang worked as a theater director in Florida. In the mid-1950s, he said, he wanted to teach at a university, but was not able to get a job. Then he turned to business and to teaching in high schools.

"Finally, I wanted to get out of the dog-eat-dog of business," Lang explained. "of the clutching against the wall. And I found out that the clutching was still there [in teaching], but at least I was dealing with the kids and with ideas . . . I want them to learn to think and that's why it's fun for me. I don't always win, but it's never boring."

In the classroom, his students say Lang himself is seldom boring. Often his voice and gestures are dramatic. His humor grabs attention even when the subject does not, though during the past four years this has caused him many problems.

When Lang caught students chewing gum too loudly, he said he often gave them the choice of giving up their morning break for detention or putting the gum on their noses. Most put it on their noses, Lang said. But when one student complained, Lang said principal Willens ordered him to stop the practice because it was humiliating to students.

"After that, I told them, they'd have to have detention," Lang explained, "because I can't humiliate you any more. And this kid said, 'Aw Mr. Lang, can't I put it on my nose? Humiliate me.' So I was bad, I guess, and I let him."

Lang said he also drew reprimands from Willens for making what she considered to be "sexist" remarks to his students. One comment, he said, was a rather shopworn old saw about how long an assigned paper should be -- "Just as long as a woman's skirt,

Also proscribed by the principal, Lang said, were a series of "grammatical grimaces" which he used to try to motivate students to pay attention to grammar. One of these was a question: "Which photograph is a threesome? (A) We have a photograph of Raquel Welch, Daddy and I. OR (B) We have a photograph of Raquel Welch, Daddy and me." Another was a remark by a professor, pointing to a shapely coed. 'An ly can make a great difference . . . For instance, it makes a difference whether you look at her sternly or look at her stern.'"

When Willens told him to stop using the material, he did, Lang said. "There wasn't anything wrong with it," he remarked. "But it wasn't worth the trouble [to keep using it]. I wasn't going to get into a great confrontation."

At other times, though, Lang has gotten into major confrontations. One was at Sherwood High School, where he taught for four years. There, Lang accused the principal of raising improperly the grade of a student whom the teacher caught plagiarizing material on a long essay. The principal won on a grievance that Lang filed, and the teacher said he was then "traded" to Woodward for another out-of-favor teacher.

Lang also has complained that principal Willens raised grades at Woodward and didn't give him strong enough backing on discipline, charges that the principal strongly denies.

He said he decided to use Aristotle's "Poetics" and Machiavelli's "The Prince" as a way to add depth to the standard 10th grade study of Shakespeare's "Julius Caesar."

Students are assigned to Lang's sections without choice, as they are to all required courses. His classes, he said, cover a wide middle-range of students who are "the most challenging to teach if you give them something to reach for."

"Yes, the material is kind of tough," Lang said, "but they can get it. The tougher I made it, the more they wanted it. And I want to raise the standards. I like that."

Seventeen-year-old Duke Sarris, who took Lang's course two years ago, said, "When you come to this school, most of the teachers are very easy with sophomores. They treat you like children. But Mr. Lang says I'm going to prepare you for college if you want me to or not, and I thought he was a fabulous teacher . . . He failed me one [marking period] but I went from there to an A. If you work hard and want to learn, you can handle the work, definitely."

But principal Willens said four or five parents complained that Lang's work was too difficult, and that it clearly went beyond the curriculum. She said her other disputes with Lang had nothing to do with the move to discipline him for teaching the unapproved books, and that she and English resource teacher Evelyn Wittman, who also ordered him to stop using Aristotle and Machiavelli, both gave Lang good ratings as a teacher.

"I have to do what I am hired to do," Willens said, "and one of my responsibilities is to see that the county curriculum is followed in this building. Sure, it sounds great: He's dealing with Machiavelli. But teachers could be adding a lot of other things, and there'd be chaos . . .

"Teachers should have a lot of freedom," she continued. "That's good. There are hundreds of books on the approved list for 10th grade English. But we can't have license. We're not in a private school. We're part of a public school system, and we have to have a curriculum, and not just rely on the capriciousness of each teacher and principal."

Lang, who has been home on administrative leave (with pay) since August, sees it all much differently, of course.

"Listen, I'm no saint. I'm a sinner," he said. "I don't like self-righteous crap. But I really believe that if you see evil and do nothing, you perpetuate it. Those are my constitutional rights that, are being jeopardized and the rights of every teacher. So I have to fight it."