IF you want to understand how great teachers transform lives, listen to the story of Olly Neal.

A recent study showed how a great elementary schoolteacher can raise the lifetime earnings of a single class by $700,000. After I wrote about the study, skeptics of school reform wrote me to say: sure, a great teacher can make a difference in the right setting, but not with troubled, surly kids in a high-poverty environment. If you think that, or if you scoff at the statistics, then listen to Neal.

In the late 1950s, Olly Neal was a poor black kid with an attitude. He was one of 13 brothers and sisters in a house with no electricity, and his father was a farmer with a second-grade education. Neal attended a small school for black children — this was in the segregated South — and was always mouthing off. He remembers reducing his English teacher, Mildred Grady, to tears.

“I was not a nice kid,” he recalls. “I had a reputation. I was the only one who made her cry.”

Neal adds: “She would have had good reason to say, ‘this boy is incorrigible.’ ”

A regular shoplifter back then, Neal was caught stealing from the store where he worked part time. He seemed headed for a life in trouble.