Classroom A205 at Montgomery Blair High School bespeaks a love of order. Maps, color photos and diagrams of such historic sites as Shakespeare's Globe Theater are arrayed neatly on the walls. Books are stowed out of sight in cabinets.The chairs form rows pointing toward the desk of David Bridges, teacher of social studies at the Silver Spring school for the past 20 years.

To students, he is "Mr. Bridges."

From the beginning in his course, they know what he expects of them. Their notebooks contain a mimeographed syllabus that schedules page-by-page reading in the textbook and section tests (four major ones per semester). Quizzes, some of them unannounced, keep students on their toes.

Across the county at Walt Whitman High Richard Abell's classroom has the informality and clutter of an artist's studio. There are potted plants, Asian proverbs tacked to the walls and a coffee pot (Abell sells coffee to students at 10 cents a cup). Students sit five or six to rectangular tables that are arranged to form a rough circle.

He asks that students call him "Richard."

Abell's students get precise textbook assignments. But there are no quizzes or section tests, only a final exam. During the semester, students write analytical essays in class based on questions Abell announces beforehand. Subject matter might be the causes of the Chinese revolution or the best direction for American foreign policy.

This is how two teachers, both well received by students, approach the same subject -- world history 88 and it illustrates an overlooked point in Montgomery County's long debate over curriculum and teaching methods: In the classroom, the teacher generally gets his way.

Reflecting the shifting majorities of its members in the last decade, the school board's emphasis has gone from structure, to innovation during the "greening" of the late 1960s and early 70s, and today Back to Basics. These changes in philosophy had some concrete effects 88 in new courses such as black history and in programs such as school-within-schools for exceptional students. In a few cases, changes in philosophy forced major changes in teaching. New Math did that in the 1960s and Back to Basics could do it in the 80s.

But those are the exceptions. In general, day-to-day routines in the classroom once the doors are closed have hardly been touched.

While administrators occasionally step in with specific orders -- as in the celebrated case of Woodward High School teacher Cyril Lang, now under threat of suspension for refusing to stop using Machiavelli's The Prince and Aristoltle's Poetics in his 10th grade English class -- Dave Bridges' attitude toward guidance from above is not unusual.

"I ignore it," he says. "Everyone ignores it." In Bridges' 20 years at Montgomery Blair, evolution in educational theory -- much of which he dismisses as "vogueishness" -- as not once altered his classroom style. "We're the professionals. We're the ones who know how to do it."

Dr. Lois Martin, curriculum director for Montgomery County's school system, agrees. "The typical teacher," says, "doesn't need a lot of supervision."

Curriculum guidelines and approved book lists are occasionally issued by the school board, but teachers say they are cast in such broard terms that just about any course design falls within them. Teachers might be told to teach the Civil War, but how they do it left to them.

Dave Bridges' ideas about his job start with the premise that students are not adults, "Students need a structure, a discipline . . . They need a teacher with a set of standards by which they can compete with themselves," he says, and he complains that many students today lack competence in even basic skills like reading.

For him, a prime goal is to train students to analyze, to determine whether a newspaper article or TV historical drama depicts its subject fairly, for instance. Such a skill, he maintains, requires firm founding in the factual heart of the discipline and persistence to finish the job.

Students rate Bridges as fair but hard. One 12th-grader said: "Most people like him. But he's fairly tough. He expects a lot out of you."

Despite the demands, he is also known as a classroom entertainer, a man whose lectures contain a joke or the odd historical fact that will bring an event to life over the distance of centuries. "He'll talk about the personal life of a king," says Carolyn Kisliuk, one of his history students. "He makes it very interesting."

At 10 o'clock one morning recently, he opened a class on the Soviet Union with a 20-minute National Geographic film on the land and people of Siberia. The lights back on, Bridges stepped to the front and began an informal lecture, unrolling a map to show how Siberia begins east of the Ural Mountains, pointing out the politicial satire in a circus clown act shown in the film.

Bridges addressed some thoughtful questions to his students, but many of the questions centered on details in the film. For instance, its narrator had described trailer trucks which were shown hauling goods along a frozen highway in Siberia.

"How many panes [of glass] in the cab of the truck?" Bridges asked.

"Three?" a student offered.

"No, two," came the answer from Bridges.

Stressing detail "teaches the skills of listening," Bridges explained later. His years in the classroom have shown that students will often create "facts" when they're unsure of what they heard.

He drilled students on the full name of the Soviet political unit that includes Siberia and European Russia. Again, some hestitation. The answer: Russian Soviet Federated Socialist Republic. Students did well to write that one down: In question 17 of a quiz the following day, Bridges asked for it again, his five-word answer space giving a subtle jog to foggy memories.

Richard Abell, a social studies teacher at Walt Whitman since the school opened in 1963, doesn't think his students would not do well on exams stressing survey knowledge and specifics. Abell says he prefers that students know a few important subjects in depth and be able to research unfamiliar ones put before them.

In some aspects -- stress on analysis -- Abell's rhetoric is close to Bridges' stated goals. But their fundamental difference seems to be that in Bridges' class, if necessary, students are made to learn. In Abell's they are expected to want to learn.

"He treats us very much as adults," says Andrea Vayda, an 11th grader. "It's a very relaxed environment. We can go and get coffee or tea." Another 11th grader, Charlotte Worrell says: "Everything's so open. It's a discussion, not him teaching you . It's fun, I like it." Both agree, however, that some students have trouble adjusting to the informality and lack of structure.

How much learning takes place is to a large extent up to the individual, according to student Peter McMahon. "If you work hard, he'll tell you everything he knows. But if you don't he won't punish you with tests."

To prepare for one recent class, part of a month-long examination of the Middle East, Abell had his students color in the region's countries and major geographical features on maps. But instead of quizzing them, as Bridges did, he tossed out a discussion question designed to bring some meaning to the exercise in cartography: What stuck you about the geography of the region?

One student responded that there were few rivers. Very well, what can we say about how people who inhabit dry areas make a living? Abell countered. Talk moved on to cities and why they grow up where they do.

One student suggested the sea had isolated the region. Abell protested good-naturedly: "Do you want to reconsider?" Water transport, he said, is still the most efficient.

During the class, Abell's role was more to direct discussion than to lecture. Students did most of the talking. A few posed questions that bordered on the smart-aleck and some stayed quiet, like a boy who absent-mindedly colored in the map he was supposed to have done at home.

Four to eight times a semester, Abell assigns an essay, to be researched on the students' own time but written in class. On China, for instance, he might ask for an analysis of how the Communist revolution of 1949 developed. "It requires them to organize a lot of material, a lot of ideas," Abell said. They are asked to cite specific facts to support their arguments but to offer generalizations as well. Last semester their essay was cast as a letter to Ronald Reagan outlining foreign policy changes they would like to see.

Before class, Abell recalled fondly the enthusiasm of students in the 1960s and early 70s and teachers' seminars he attended when academic reform was blooming. "Some of the most exciting intellectual experiences I've ever had were in those workshops," he said. They brought extensive modification in his own teaching style.

That time, though, is gone, and Abell has had to discontinue some of his more unorthodox practices, such as convening a mock city council where students delivered their own presentations.

The school board now wants department-wide final exams in each course at a given school, part of an effort toward continuity in teaching content. So Abell is now working with colleagues who teach his subjects (often with a more traditional emphasis) to devise a test that will somehow be fair to everyone's students.

In the long run, teachers could run into more intrusions like this from the Back to Basics effort. It seeks to make students competent in 100 specific tasks and fields, ranging from checkbook balancing to citizenship, deemed necessary for survival in the real world. Someone will have to teach these things -- and Bridges and Abell could end up with a share, like it or not.