When you meet Robert M. Morgenthau, it feels like nothing has changed. His office on the 31st floor of Wachtell, Lipton, Rosen & Katz is as messy as ever. His assistant, Ida Van Lindt, is still with him after 44 years. The photos of him with John F. Kennedy, Martin Luther King Jr. and Lyndon Johnson still adorn the wall. And they still call him boss. But of course, a decade has passed since Morgenthau, New York City's longest-serving district attorney, was one of the most feared men in America. And it's no surprise that as he approaches his 100th birthday, he has had to make some concessions to age. His booming voice is gone, he whizzes around in a wheelchair and he no longer jumps rope with the kids in the Police Athletic League programs. Nevertheless, there is one point on which he is adamant. It is too late to retire. "My grandfather used to say opportunity comes to everyone. The secret is to recognize it and not let it go by. I didn't recognize the opportunity and let it go," he confides in an interview last week with the Law Journal. When was that? "At age 65 or 70," he replies. Are you sorry you didn't retire? "No," he says and for just a minute the booming voice is back and the blue eyes twinkle. "It's always been a pleasure for me to go to work." In contrast to the years when he was a constant presence on the nightly news and the model for DA Adam Schiff on "Law & Order," Morgenthau hasn't been in the spotlight nearly as much at Wachtell. But that's changing in a big way as admirers celebrate his 100th birthday at eight different events. The Fund for Modern Courts honored him last Wednesday. Chief Judge Robert A. Katzmann of the U.S. Court of Appeals for the Second Circuit, who bestowed the John J. McCloy Memorial Award on him, enthused: "It is no exaggeration to say that there is no one in the history of this nation who has done more over a lifetime to serve the public than he. "At a time when immigrants have been under siege, he has championed the rights of immigrants," Katzmann said. "He has spoken on behalf of veterans, on behalf of inmates on death row, in support of pleas for clemency, maintaining his high level of activity with organizations like the Police Athletic League and the Museum of Jewish Heritage." Last Thursday night, he was roasted by about 100 assistant U.S. attorneys who worked for him from the time he was appointed U.S. attorney for the Southern District of New York by John F. Kennedy in 1961 to 1970 when he was forced out by Richard M. Nixon.

On June 17, the Manhattan District Attorneys' Association will fete him. Associate U.S. Supreme Court Justice Sonia Sotomayor is planning to be there. Sotomayor worked for Morgenthau when he was DA, as did Gov. Andrew Cuomo, John F. Kennedy Jr., Robert F. Kennedy Jr. and Cyrus Vance Jr. All told, he supervised 3.5 million prosecutions, including John Lennon's killer, Mark David Chapman, subway vigilante Bernie Goetz and preppie killer Robert Chambers.

Eight days later, he will be the guest of honor at the Police Athletic League Superstar Dinner, which is in recognition of his 56 years as its leader. U.S. Attorney for the Southern District Geoffrey Berman is having a party for him on July 30. There's a family party (he has seven children, six grandchildren and three great-grandchildren) on his birthday, July 31, and another on Martha's Vineyard, where his extended family gathers every August. Wachtell, where he is of counsel, has an event in the works, too.

As he approaches his 100th birthday, Morgenthau still works almost every day from Wachtell's offices on West 52nd St. or from his Upper East Side home. His mission now is to inspire young attorneys to understand the plight of immigrants and the less fortunate.