As is often the case with exhaustion, the clues were there all along, but no one outside his family had any reason to slow Rudenstine down. ““I’ve never seen anyone work harder than Neil,’’ said Bill Kovach, curator of Harvard’s Nieman Foundation and a former New York Times editor. ““He looked tired, but nothing unusual,’’ said Harvard football coach Tim Murphy, who hosted the president at a team dinner on Nov. 21, Rudenstine’s last public appearance. Indeed, most at Harvard regarded Rudenstine’s visible weariness simply as something that is endemic in our modern workaholic society.

Appointed three years ago – Harvard’s first Princeton-educated, first Jewish-Catholic president – Rudenstine hit the steps of Widener Library reaching and thinking. He reached out to undergraduates, attending dinners at the famous houses that line the Charles River, and holding regular visiting hours in his office. He reached out to staff. The smiling, slender Renaissance-lit scholar would stop and chat with anyone from custodians to emeriti as he marched from engagement to engagement. He was as famous for his incessant personal note-writing as another president, George Bush.

Since Rudenstine’s arrival at Harvard in 1991, the university announced its audacious $2 billion, five-year fund-raising campaign. That’s a huge figure made manageable only because it includes almost every dollar the university would have collected anyway. Still, the campaign was expected to net at least a 25 percent premium, so the stakes were enormous. Rudenstine’s vision demanded that the fund drive be more than the usual alumni-dunning affair. Besides promising nameplates on buildings and 50-yard seats at The Game, he wanted to use a bit of the money to transform the intellectual life of the Harvard elites. His idea: promoting major interdisciplinary efforts among Harvard’s 15 schools. But as president he could not simply order those initiatives.

Most of the financial clout in Cambridge is held by the separate schools. By most accounts Rudenstine’s office controls just 1 percent of revenues. To persuade the deans to cede staff and money for joint projects, Rudenstine met, cajoled, negotiated and met some more. He finally wrested agreement for five new universitywide programs. The best known is called Mind, Brain and Behavior, which unites experts in medicine, psychology, religion, comput-er science and cultural anthropology.

Because Harvard is, of course, Harvard, Rudenstine’s efforts got national attention. So, too, now has his health. Nothing in Rudenstine’s career climb – from Rhodes scholar to revered professor, to Princeton provost, to No. 2 at the prestigious Mellon Foundation – could have prepared him for life in the Cambridge fishbowl. Now he is resting at home amid the inevitable speculation about his future. It hasn’t helped that Dean Daniel C. Tosteson of Harvard’s Medical School was saying Rudenstine’s condition was ““of unknown origin.’’ His mother told The Boston Globe that her Neil was ““just worn out.’’ And Friday night his wife, Angelica, gave a brief talk at a party honoring David Rockefeller for his $11 million gift establishing a Latin American studies center at Harvard. She made it clear her husband would have done nearly anything to attend. ““He works hard – probably too hard,’’ she said, ““but I want you to know he is really resting. He is recharging his batteries day by day.''

Harvard’s board immediately named provost Albert Carnesale acting president. He’s the dean of the Kennedy School of Government, a nuclear engineer by training who became an arms-control expert. ““I think this is a pretty large ship that can stay well on course’’ until Rudenstine returns, Carnesale said. Friends hope that when he does return, he can claim to be something that apparently no other university president in the country is – well rested.

PHOTO: Rudenstine: “I’ve never seen anyone work harder than Neil'

< b>RUDENSTINE’S REALM

Harvard’s president is not the master of all he surveys. His job is burdened by all the usual academic issues–and meddling alumni, fund-raising needs and P.C. skirmishes. A scorecard:

  1. Wealthiest and most independent are medicine, business and law.

$29 billion, most controlled by deans

Faculty tenure, naming and removing deans, negotiating campus disputes

Highly accessible to all, started five universitywide interdisciplinary programs