Jaime Escalante didn't just stand and deliver. He changed U.S. schools forever.

From 1982 to 1987 I stalked Jaime Escalante, his students and his colleagues at Garfield High School, a block from the hamburger-burrito stands, body shops and bars of Atlantic Boulevard in East Los Angeles. I was the Los Angeles bureau chief for The Washington Post, allegedly covering the big political, social and business stories of the Western states, but I found it hard to stay away from that troubled high school.

I would show up unannounced, watch Jaime teach calculus, chat with Principal Henry Gradillas, check in with other Advanced Placement classes and in the early afternoon call my editor in Washington to say I was chasing down the latest medfly outbreak story, or whatever seemed believable at the time.

Escalante, who died Tuesday from cancer at age 79, did not become nationally famous until 1988, when the feature film about him, "Stand and Deliver," was released, and my much-less-noticed book, "Escalante: The Best Teacher in America," also came out. I had been drawn to him, as filmmakers Ramón Menéndez and Tom Musca were, by the story of a 1982 cheating scandal. Eighteen Escalante students had passed the Advanced Placement Calculus AB exam. Fourteen were accused of cheating by the Educational Testing Service, based on similarities in their answers. Twelve took the test again, this time heavily proctored, and passed again.

Whether they cheated was an intriguing mystery, but not the one that kept me hanging around Garfield. I wanted to know how there could be even one student at that school taking and passing AP Calculus, perhaps the hardest course in American secondary education. Garfield offered the worst possible conditions for learning: 85 percent of the students were low income, most of the parents were grade-school dropouts, faculty morale was bad, expectations were low.

Yet the school had produced phenomenal results that would challenge widespread rules barring average and below-average students from taking AP classes. The stunning success at Garfield led U.S. presidents to endorse Escalante's view that impoverished children can achieve as much as affluent kids if they are given enough extra study time and encouragement to learn.

In 1987, 26 percent of all Mexican American students in the country who passed the AP Calculus exams attended a single high school: Garfield. That meant that hundreds of thousands of overlooked students could probably do as well if they got what Escalante was giving out. But what was that?

Whenever I suggested that the great teaching I was seeing at Garfield might be the reason so many students were succeeding in AP, people at parties dismissed me as romantic and naive. I was living in Pasadena, where my children, like my neighbors' children, attended private schools. People there didn't believe in teaching; they believed in sorting. The idea that the sons and daughters of immigrant day laborers and seamstresses could be made to comprehend calculus, the intellectual triumph of Isaac Newton and Gottfried Leibniz, made no sense to them.

"I bet if you checked out their backgrounds, you will find those teachers are skimming off the few kids whose parents went to college," one professor told me. More common was the assertion that Escalante, and the school's splendid history and government teachers, drilled enough facts and formulas into their kids to fool the AP tests but had no chance of giving them the conceptual understanding that well-prepared suburban students developed.

These theories quickly fell apart. I surveyed 109 Garfield calculus students in 1987 and found that only nine had even one parent with a college degree, and that only 35 had a parent with a high school diploma. The engineering and science professors at USC, Harvey Mudd and the other California colleges recruiting Garfield grads laughed at the "no conceptual understanding" myth, as did the Escalante students I started running into who had become doctors, lawyers and teachers.

It took me several years to understand how Garfield's AP teachers, and the many educators who have had similar results in other high-poverty schools, pulled all this off. They weren't skimming. It wasn't a magic trick of test results. They simply had high expectations for every student. They arranged extra time for study -- such as Escalante's rule that if you were struggling, you had to return to his classroom after the final bell and spend three hours doing homework, plus take some Saturday and summer classes, too. They created a team spirit, teachers and students working together to beat the big exam.

Escalante celebrated "ganas," a Spanish word that he said meant the urge to succeed. He was so convinced of the power of teaching that he lied to keep students with him. He said school rules forbade dropping his class. He told the parents of absent students that if he did not see their children in his classroom the next day, he would call the immigration authorities to check on their status.

I left Pasadena and moved to Scarsdale, N.Y., in 1992. At Scarsdale High School, I had a shock. My younger son wanted to take AP U.S. history. I assumed that, like Garfield, the school would welcome anyone with the gumption to take such hard course. Instead, he was told he could get in if he passed an entrance test. Once again I was in a land ruled by sorting, not teaching.

There are fewer schools like that now, largely because of a change in teacher attitudes. My annual surveys of AP participation for Newsweek magazine show schools like Garfield emerging all over the country, particularly in the Washington area. Low-income students are being offered a chance to challenge themselves. Those schools are full of educators who tell me they have read everything about Escalante.

When I discovered that his vocabulary was spreading even to grade schools, I knew that he had triumphed over those who wouldn't even open the AP door to some students. In 2001, a fifth-grade teacher in Southeast Washington told me that she had instituted "ganas points" for students who took an extra step to help themselves and others prepare for college. That school became the KIPP DC: KEY Academy, the city's top-performing public middle school.

Escalante liked that story when I called him in Bolivia. It was amazing, he said, what teachers could do if they believed in their kids. He said he was still teaching. He was never going to stop.

When I got a call a couple of days after his death about another school planning to open AP to all, I decided he was exactly right.