The public policy scholar’s A Perfect Turmoil (Bellevue, Apr.) reveals the outsize impact a turn-of-the-20th-century doctor had on how disability is perceived and treated.

How did you come across Walter Fernald?

The Fernald School is a few miles from where I live. But nobody I asked seemed to know who he was. So I thought, I’ll do research, I’ll go look for documents. But everybody said they’ve all been destroyed. I went to the state archives and asked, “Do you have absolutely anything by Walter Fernald?” The archivist laughed at me; turned out they had 65 boxes of his correspondence alone. What I discovered is that Fernald was a monumentally important figure in almost every aspect of how we see intellectual and developmental disabilities. His influence is hard to overstate. He was the first person to create an outpatient clinic where you could take your kid to get a medical examination for intellectual disabilities. But he was also a leading figure in the early eugenics movement, before breaking with the eugenicists over the idea of sterilization and becoming the first anti-sterilization advocate. And after having spent a lifetime building institutions for disabled children and persuading others to do the same, he had this complete shift in thinking a half century before the rest of the world got there, saying that we need to shut these places down and what we really need is to be better people—to be good to disabled people who live in our communities, not send them away. It blew my mind that nobody talks about him.

You portray him ambivalently. Why?

He’s messy. Fernald wanted to help people, but he did terrible things. First, he created a utopia for disabled kids, effectively arguing, “The world is really bad to disabled children and I need to protect them.” Then he had this monstrous shift where he said, “Maybe I was wrong about this, maybe what I need to do is protect the world from them”—falling into what I think he aptly called this period of deep pessimism, his eugenics period, where he goes in a completely disturbing direction, coming to believe that disabilities were expressed as delinquency, bad behavior, sexual promiscuity. He influenced many others into thinking those things as well. But he interrogated his own beliefs relentlessly, until he eventually publicly denounced himself, saying, “I was wrong and this was bad.” This man destroyed a lot of lives to get the answers he was looking for.

How did he shape what we know as dis- ability care today?

The outpatient clinic that he created is the beginning of special education. The idea that you could go to a specialist and not put your kid away in an institution begins with him. Today, 7.5 million children in the U.S. are eligible for special education services; that is directly the impact of Walter Fernald.