Bratton to Lead New York Police for Second Time William J. Bratton was named police commissioner of New York City for the second time on Thursday. But it is a different place than the crime-ravaged city he came to in 1994. And he said he was going to be a different kind of commissioner, overseeing a different kind of policing. "In this city, I want every New Yorker to talk about "their police," "my police," " Mr. Bratton said after his appointment was announced by Mayor-elect Bill de Blasio, before reading from a children's book about police work he said he had cherished since he was 9. In 1994, the message was different: "We will fight for every house in the city; we will fight for every street; we will fight for every borough," he said at the time. And we will win. Back then, the hard-driving, press-savvy Mr. Bratton could be found dining out among city luminaries, and on the covers of newspapers and national magazines. He received a lot of credit for historic drops in crime rates, even as the trends in New York coincided with those around the country. Such prominence drove a very public wedge between him and Mayor Rudolph W. Giuliani, a former prosecutor, who pushed him out just two years after appointing him. The mayor has the full authority to hire and fire the commissioner. On Thursday, Mr. Bratton, 66, said he had "learned a lot" since the last time he ran the New York department, the largest in the country, and people familiar with his thinking suggested that significant changes were in store. Before making the decision to bring him back, Mr. de Blasio said he had been reassured by conversations with others who had worked with Mr. Bratton, especially in Los Angeles, where he lead the police from 2002 to 2009. Mr. Bratton said: "I report to the mayor. I am not the mayor. But his is perhaps the single most important and visible appointment to be made by Mr. de Blasio, who was elected partially because of his criticism of the police's aggressive use of the stop-and-frisk tactics. Mr. Bratton has been in law enforcement for four decades, including stints as commissioner in Boston as well as Los Angeles, but this may be his biggest challenge: keeping crime at historic lows - just more than 300 murders so far this year - while mending the relationship with minorities, and not upstaging his boss. In January, Mr. Bratton will replace Raymond W. Kelly, the police commissioner since 2002. A bright mood reigned at a community court in Red Hook, Brooklyn, where Mr. de Blasio made the announcement, which had been widely anticipated. The mayor-elect referred to an old headline calling Mr. Bratton "America's Top Cop" before allowing him to take the microphone. "Welcome back," Mr. de Blasio said. "You would bring that magazine cover up," Mr. Bratton replied. It was a moment of glory light years from the day Mr. Bratton began his policing career in Boston in 1970. He still speaks with the city's accent. He first came to New York to lead the transit police in 1990, going after fare-beaters and other low-level offenders in broad sweeps that also caught more serious criminals. The approach was derived from the "broken windows" theory of policing, which holds that by cracking down in troubled neighborhoods on small but highly visible crimes of disorder such as turnstile jumping and prostitution, more serious crimes fall as well. It is a theory that Mr. Bratton has long espoused. Some researchers over the years since have questioned the efficacy of the theory, but Mr. de Blasio said he was a firm believer that it worked. From the transit police he moved on to lead the Boston Police Department briefly before returning to New York City as commissioner in 1994. It was at a time when murders were around 2,000 a year, when squeegee-men were a fixture on the streets, and drug-dealers and prostitutes flourished in the open. It was also a time of widespread corruption in the department. Joseph Goldstein and William K. Rashbaum contributed reporting.