Sam Tsemberis was not any kind of expert on housing in 1992 when he came up with Housing First, an idea that has revolutionized how many projects and policies aimed at ending homelessness approach their work. But now he is, and that idea has inspired a great deal of research and innovation.

Born in Greece and raised in Montreal, he trained as a clinical psychologist in New York City in the early 1980s. And as he walked to work in the morning, he realized that he was seeing many people living on the street who had been treated at the hospital the previous month. This group of people began to attract labels – treatment resistant was one. In other words, somehow being homeless was their fault.