Adam Moss, editor in chief of New York Magazine for the past 15 years, said Tuesday that he’ll be stepping down in March. One of the leading magazine editors of his generation, Moss, 61, is the longest-serving chief in the magazine’s half-century history. Pamela Wasserstein, the chief executive of New York Media, is expected to announce his successor later this week. Moss’ editorial ethos and journalistic sensibility permanently reshaped several of the country’s biggest publications, including at The New York Times Magazine, where he was editor for five years, and helped create the Times’ Styles section. “I’ve been going full throttle for 40 years; I want to see what my life is like with less ambition,” Moss told The New York Times. “I’m older than the staff. I’m older than the readers. I just want to do something new.” Moss says he has no plans after his departure, aside from a long-awaited vacation.