Nicknamed "Needle Park" at the time (as were many parks in the city), it was considered a "no-go zone" by New Yorkers at the time. Part of the problem was Robert Moses's 1930 redesign, which made the park practically hidden to passerby, and thus the perfect hideout—in fact, in 1980 one of the Bryant Park Corporation founders told the NY Times, “It’s incredible, but it seems the park was designed for pushers.” Eventually, a new day was upon us, and according to The Internet:
From 1979 to 1983, a coordinated program of amenities, including a bookmarket, a flower market, cafes, landscape improvements, and entertainment activities, was initiated by a parks advocacy group called the Parks Council and immediately brought new life to the park—an effort continued over the succeeding years by The Bryant Park Restoration Corporation, which had been founded in 1980 by a group of prominent New Yorkers, including members of the Rockefeller family, to improve conditions in the park.
Here are some photos of the park in the early 1980s, a few years before the 1988 redesign, showing New Yorkers enjoying the piece of land.
[via the BPC]