From the NYT obit:
Most important, he is credited with leading the city government back from near bankruptcy in the 1970s to prosperity in the 1980s. He also began one of the city’s most ambitious housing programs, which continued after he left office and eventually built or rehabilitated more than 200,000 housing units, revitalizing once-forlorn neighborhoods.
Politically, Mr. Koch’s move to the right of center was seen as a betrayal by some old liberal friends, but it gained him the middle class and three terms in City Hall. He was also the harbinger of a transformation in the way mayors are elected in New York, with candidates relying less on the old coalition of labor unions, minority leaders and Democratic clubhouses and more on heavy campaign spending and television to make direct appeals to a more independent-minded electorate.
A life long bachelor, Koch was often asked about, but refused to acknowledge, his gayness. Four years ago he spoke to the New York Times about being asked.
Here’s the official trailer to the film “Kock” – a documentary on the former mayor: