But here's another way to view Arndt's commitment, his determination to stay involved in patients' care even after they had ceased to be his patients. "He didn't necessarily know where to draw the line," says Stephen Lipson, who was chief of orthopedics at Beth Israel during Arndt's residency. Maybe that surplus of compassion and of self-centeredness came from the same place. "He wanted to be in charge," Lipson says.

Lipson had known Ken Arndt since their residency days at Massachusetts General Hospital, and thought the world of him. Now, here they were, both chiefs at Beth Israel, both watching their own sons follow in their footsteps. (Lipson's son was several years behind David at Harvard Medical School.) "Ken and I had a real kinship," he says.

Lipson found David to be a superior surgeon in the OR and intellectually stimulating outside of it. So he took him under his wing. While David would soar to great heights, it would be prove to be a bumpy flight.

"David wanted nothing but exceptional results," says Lipson, a soft-spoken fifty-seven-year-old who now works at Harvard Vanguard Medical Associates. But he says Arndt's interpersonal skills didn't always measure up, whether he was twisting around language to confuse people or tearing into them. "If a nurse was doing something and he didn't like the way it was being done-a dressing change, medications, or whatever-he might bark at them: "No, you shouldn't do this! It's wrong! Do it this way! He wanted to run the show. Some nurses would go away crying." Lipson would take him aside, tell him to cool it. "But he would just commit the same flaw another time," Lipson says. "He could not turn himself off from being himself."

Lipson was particularly troubled by one area of Arndt's behavior that arose as his residency progressed. Some male orderlies and nurses were complaining that Arndt had made what they felt were inappropriate comments to them, he says. "I had to warn him not to pursue sexual interactions with other male staff," Lipson recalls. "Otherwise it was going to be a problem, and he could be chastised and reported to the administration."

But still, but still: David Arndt was an extremely gifted surgeon. Lipson found him fun to teach-he would do research on his own, push relentlessly for higher performance from everyone, especially himself. Although some of his patients were put off by his manner, most loved him-they could tell he genuinely cared about what happened to them.

And around this time, friends say, Arndt began talking about needing to get his personal life back in order so he could be a good role model-for his son. Arndt told friends that the boy had been born during his early days in San Francisco, but that it was only after the boy was in his teens and wrote to Arndt that the connection was revived. Arndt kept a picture of him, proudly updated his friends on the teen's achievements in school. One time when Arndt was visiting California, Grant Colfax got a chance to meet the boy and his two female parents.

Things were coming together at work as well. As the capstone to Arndt's residency, Lipson advocated for him to be named chief resident at Beth Israel in 1997. Given his father's longstanding connections there, "it felt like home for David."

Lipson still envisioned Arndt becoming one of Boston's next top spine surgeons, if he could just keep himself in check. He helped arrange for Arndt to do his fellowship in spine surgery (the branch of orthopedics that is closest to neurosurgery) at Tulane University School of Medicine in New Orleans. When Arndt returned to Boston and began working at Harvard Vanguard and at a private group practice, Lipson sent him a steady supply of referrals-a crucial lifeline for a young doctor starting out in an over-doctored place like Boston.

Lipson and his wife, Jenifer, had always enjoyed socializing with Ken and Anne Arndt at hospital functions. "They're a nice Jewish couple," Lipson says, "and so are we." Still, his wife sensed trouble in his continued advocacy for David and cautioned him to keep his distance. Lipson would hear none of it. "I wanted to have to do with him," he says. "But my wife said, 'He's out of control.' Which, in the end, I think was true."

You want warning signs? They were there. In fact, the year 1998 was packed with them, though many of the people who worked with David Arndt wouldn't find out about them until much later.

When Arndt returned from New Orleans, Stephen Lipson asked his protege about his experience. Arndt told him it went great, neglecting to mention the federal law he had broken while he was there. On May 29,Alfredo Fuentes submitted a passport application under a false name, and Arndt filed a supporting affidavit. Fuentes had been Arndt's domestic partner for several years, and he had moved with Arndt from Massachusetts to New Orleans. But Fuentes was a Venezuelan who was in the States illegally. The fraudulent passport application, Arndt would say later, was their attempt to head off deportation.

Three months later, in the early morning hours, Fuentes was sitting on a bedroom couch talking to a man named Roger Volzer in Volzer's Provincetown home on Cape Cod. After Volzer got up to blow out some candles, Arndt, who had been staring at the men through a window, used his surgeon's hands to rip out a screen and climb into the house, according to the Provincetown police report. Volzer would tell police that Arndt punched him in the head, pushed him out of the bedroom, and then threw a chair at him. Arndt was charged with assault and battery, burglary, and malicious destruction of property.

Volzer eventually decided not to press charges in exchange for Arndt's agreeing to pay him $30,000 and to attend weekly anger-management counseling. Christopher Snow, Volzer's attorney, says Arndt's supporters lobbied his client, telling him a conviction could derail a promising medical career.

But if Arndt dodged a bullet, he hardly acted grateful during their meetings, says Snow. "In the 'if looks could kill' category, he was a murderer. He acted if the proceedings were an incredible invasion on his otherwise important life. He had absolute contempt for the fact that someone might have the audacity to hold him accountable for his bizarre and destructive behavior."

In the end, Snow has said,Arndt paid only $18,700 and failed to follow through on counseling.

In the fall of 1998, Arndt pleaded guilty to the misdemeanor passport violation in federal court in Louisiana. He was sentenced to three years' probation and fined $3,000. But because he had renewed his medical license a few months earlier, he would not have to report that conviction to Massachusetts authorities until his next renewal period two years later.

The fines and legal fees, meanwhile, were adding up. His breakup agreement with Goldfinger, the one that required Arndt to pay 9 percent of his income to his former partner, was slated to go into effect in 1998. So just when Arndt had finished up his lengthy medical training and was about to start making some real money- the 2002 median salary for spine surgeons was more than $545,000, according to the Medical Group Management Association-the financial vise was beginning to tighten.

Arndt argued in court filings that the Goldfinger agreement should be invalidated because he had signed it under duress. The case slogged through the courts and arbitration until a Superior Court judge upheld it in 2000. Goldfinger would never collect a dime.

Even with so many distractions, Arndt seemed able to wall off his personal problems from his professional work.

James A. Karlson, chief of orthopedics at Mount Auburn Hospital, had known Arndt since residency and practiced with him both at Harvard Vanguard and in their four-surgeon group practice. Arndt had privileges at most of Boston's top hospitals but began focusing his attention on Mount Auburn when the veteran spine surgeon there started to cut back. Karlson says there were a few low-level concerns about Arndt, such as tardiness, but no indication of his mounting personal problems. "He had certain problems that we didn't pick up on," Karlson says. "Should we have? 'Could we have?' is a better question."