CAMBRIDGE, Mass., June 14 — Harvard Law School announced today that it was starting a $400 million capital campaign, the largest fund-raising effort undertaken by a law school.

"We're seeking the unattainable," Scott Nichols, associate dean of the law school, said in an interview. "Nobody's ever dared to think about a campaign this big."


Michael Marshall, the director of academic communications at the University of Virginia Law School, said that school's last campaign, which ended in 2001, held the previous fund-raising record, $203 million.

Harvard Law School's endowment is now $840 million. Michael Rodman, a spokesman for the school, said, "We have ambitious goals and need funds to meet those ambitious goals."

The law school's last fund-raising drive, which was completed in 1995, raised $183 million, $33 million over its goal.

The campaign, which will last four to five years, has already secured $170.1 million in commitments, Mr. Nichols said. The school has been promised donations of more than $5 million each by Finn M. W. Caspersen, chairman of the campaign, and Gustav M. and Rita E. Hauser, Mr. Nichols said.

The campaign looks to address almost every aspect of the school. About $100 million will finance expansion, primarily the construction of new faculty housing. The school is also seeking $75 million in endowment funds to subsidize 15 new faculty positions and $62 million for financial aid and a loan-forgiveness program that will allow more graduates to pursue careers in public service without law school debt. The school also seeks to spend $24 million on globalization programs.

The dean of the law school, Robert C. Clark, is stepping down on June 30. He will be succeeded on July 1 by Elena Kagan, a former aide to President Bill Clinton and professor at the school since 1999.