The 59-year-old Chicago native picked to operate Monday on Massachusetts Sen. Edward M. Kennedy's cancerous brain tumor is a respected leader in the giant field of neuro-oncology who performs the vast majority of such surgeries at Duke University Medical Center.

When the top doctor at the American Cancer Society, Dr. Otis Brawley, was asked by his daughter's high school math teacher for advice when diagnosed with a brain tumor, he recommended Duke University's Dr. Allan Friedman. He "is one of the thought leaders" in the field, Brawley said.

"He's an excellent surgeon. His patients are in very good hands," said Dr. Matthew Ewend, the neurosurgery chief at the nearby University of North Carolina at Chapel Hill.

Friedman is Duke's neurosurgon-in-chief and the program director of the university Division of Neurosurgery at Duke. He also serves as the deputy director of the university's Preston Robert Tisch Brain Tumor Center. An internationally known tumor and vascular surgeon, he is responsible for more than 90 percent of tumor resections and biopsies at Duke.

Duke's brain tumor center was established in 1937 and has a staff of more than 250 who work only on the research and treatment of brain tumors. Doctors and staff there are currently following the treatment of more than 2,000 patients from around the world.

More than two-thirds of the adult brain tumor patients at Duke also take part in clinical trials, the university said, compared to only 8 percent nationwide.

Friedman is a graduate of Purdue University who earned his medical degree at the University of Illinois-Chicago, and did his residencies at Duke and the University of Western Ontario. His wife, Elizabeth Bullitt, is also a well-known neurosurgeon now focusing on research at UNC Hospitals, just eight miles from Duke.

Friedman lists his clinical interests as brain tumors, skull base tumors, peripheral nerve surgery, pituitary tumors and cerebrovascular disease, according the school's Web site.

Along with tumor research, Friedman is collaborating on research into epilepsy and hemorrhages in the space between the brain and the thin tissues that cover the brain.

Kennedy was hospitalized May 17 at Massachusetts General Hospital after undergoing a seizure at his home on Cape Cod. Doctors later announced that he had a malignant glioma — one of the worst kinds of brain cancer — in his left parietal lobe.

His decision to head to Duke, a hospital with a sterling reputation, was of little surprise to his friends.

"I think he likes to conduct an exhaustive search of resources out there and then make a decision. I think that's what all patients should do," said Philip W. Johnston, a Massachusetts Democratic activist and former chairman of the Robert F. Kennedy Memorial.