The comedian Chris Rock, who gave the often staid Academy Awards a jolt this year by mocking movie stars and taking a camera crew into a black neighborhood to talk to moviegoers, will not be returning to host next year's Academy Awards, his spokesman said. "He didn't want to do it in perpetuity," said Matt Labov, Mr. Rock's publicist. "He'd like to do it again down the road." Gil Cates, who is producing the awards program for the 13th time, would not confirm the decision, saying only that he had not yet chosen a host and that Mr. Rock did a "great job" this year. He said he would announce his choice for the March 5 broadcast on ABC before the end of the year. Sharon Waxman reports.