John E. Mack, 74, the Harvard Medical School professor of psychiatry who won a Pulitzer Prize for his biography of Lawrence of Arabia and who studied people who claimed to have had encounters with aliens, died Sept. 27.

Dr. Mack was struck by an alleged drunk driver in London and pronounced dead at the scene. He was in England to take part in at the T.E. Lawrence Society Symposium in Oxford, according to a release on the John E. Mack Institute Web site.

Dr. Mack won the Pulitzer Prize for biography in 1977 for "A Prince of Our Disorder" on the life of World War I British officer T.E. Lawrence, better known as Lawrence of Arabia.

His research about people who claimed to have had encounters with space aliens resulted in two books, 1994's "Abduction" and 1999's "Passport to the Cosmos: Human Transformation and Alien Encounters."

In studying 200 people from around the world who made such claims, he concluded that they had a heightened sense of spirituality and generally had no evidence of mental illness. He held that such encounters were real, though probably more spiritual than physical in character.

His work was the subject of the 2003 documentary film "Touched."

In 1994, Harvard Medical School initiated proceedings to review the controversial research. After a 14-month investigation, the school "reaffirmed Dr. Mack's academic freedom to study what he wishes and to state his opinions without impediment."

Dr. Mack's early work focused on clinical explorations of dreams, nightmares and teen suicide, and how world perception affects relationships. He advocated a move away from materialism in Western culture, blaming it for the Cold War and global ecological problems.

John Edward Mack was born in New York. He was a 1951 graduate of Oberlin College and a 1955 graduate of Harvard's medical school.

His marriage to Sally Stahl Mack ended in divorce, the Boston Globe reported. Survivors include three sons; a sister; and two grandchildren.

John E. Mack, a Harvard Medical School professor of psychiatry, won a Pulitzer for his Lawrence of Arabia biography and studied claims of alien encounters.