When Bill de Blasio was running for mayor in 2013, portraying himself as the candidate who would bridge the gap between the city’s rich and poor residents, his ambitious campaign pledge was to create 200,000 units of affordable housing in New York City. In a city with a growing population – and growing inequality – more and more New Yorkers were struggling to find a place to live, de Blasio said.

After winning the election, his administration quickly began work on a detailed proposal to follow through on his goal, and introduced its Housing New York plan a year ago. Leading the 10-year effort, which could define de Blasio’s legacy as mayor, is the city’s Department of Housing Preservation and Development.

The agency has already helped develop two key programs – Mandatory Inclusionary Housing and Zoning for Quality and Affordability – which were approved this year and will help pave the way for the administration to reach its housing targets. In coming years, HPD will continue to play a pivotal role in carrying out the program and navigating the pitfalls along the way.

But that only begins to describe the role of HPD, which also provides financial incentives for new housing, assists in community planning and enforces the housing code.

In City & State’s insider’s guide to HPD, we provide our readers with a snapshot of the agency’s progress in meeting its goals, a rundown of its key staffers, an analysis of its budget, and more.