Unlocking the Door: An Implementation Evaluation of Supportive Housing for Active Substance Users in New York City, the second paper released by CASAHOPESM, is a joint product from CASA Columbia and the Corporation for Supportive Housing (CSH). It is designed specifically for a policy audience, particularly government and housing organization administrators who are considering creating similar programs in other parts of the country. This project is funded by the Conrad N. Hilton Foundation.