By the early 1970s, Ace Books became a major division of the old publisher, Charter Communications, which was based out of the Hippodrome Building, 1120 Avenue of the Americas, in New York City. In 1972, Ace was acquired by Grosset & Dunlap, and in 1982, Grosset & Dunlap was in turn acquired by G.P. Putnam's Sons. Ace was reputedly the only profitable element of the Grosset & Dunlap empire by this time. Ace soon became the science fiction imprint of its parent company.