Over the next decade, Summers taught undergraduate economics classes, advised dissertation students and conducted research in areas involving both applied and theoretical economics. During that time, students and colleagues say, Summers left his mark on the careers of scores of young economists.

"There are almost no distinguished applied economists between the ages of 33 and 43 who didn't have Larry Summers as a mentor in some way," says Professor of Economics Lawrence F. Katz, who did graduate studies under Summers.

Students who impressed Summers as undergraduates became his dissertation advisees, and many followed him to Washington.

Bradford J. Delong '82, a professor of economics at the University of California at Berkeley, met Summers when a fellow economics student introduced him.

Delong was Summers' first dissertation student and became a close friend. When Summers went to the capital, Delong says, "I went along as a spear carrier."

Summers' chief of staff, Sheryl K. Sandberg '91, also met her future boss at Harvard: she wrote her thesis under his supervision.

One of Sandberg's predecessors at Treasury, Sylvia M. Mathews '87, says mentoring is one of Summers' greatest strengths, a valuable asset for a presidential contender, especially at the College--an area of particular concern for the search committee.

But Summers' former students remember their relationships with Summers at Harvard for more than the influence he had on their careers. It was at Harvard that many colleagues got their first sense of the breadth of Summers' intellectual pursuits.