As the obituary notices will tell you, Samuel Huntington was a controversial figure. They lead, normally, with a reference to "Clash of Civilizations?" his 1993 Foreign Affairs article, which outraged many readers by predicting that the end of the Cold War would usher in, not an era of good feelings and international cooperation, but rather antipathies more deeply rooted than the tensions between states. It was vintage Sam--tough-minded and lucid, bringing scholarship to illuminate the problems of the political world. Reasonable critics confessed themselves unsettled by it, and some have even ruefully conceded that Sam got it more nearly right than they did.

If the journalists do a bit more investigating, they discover that Sam was the greatest political scientist of his generation. They might note, for example, that in 1957 he published The Soldier and the State, a landmark work on civil-military relations with which the rest of us interested in the subject still wrestle. Not many 30-year-old assistant professors write books that live half a century later. Some mention Political Order in Changing Societies (1968), an equally monumental work in a completely different field, political development, or his writings on American politics and foreign policy.

Sam's numerous books and no less important articles (I still assign a 1962 essay, "Patterns of Violence in World Politics," in one of my courses) are a staggering corpus of work. But they represent only a portion of his legacy. For Sam has left behind him a vast array of students, in government, journalism, and business, who are what they are in part because of him. Some of them followed his path to academe--they include professors at Columbia, Princeton, Harvard, and many other institutions--because they were inspired by an academic ideal that he embodied. I know, because I am one of them.

I had my first encounter with Sam as an undergraduate, timidly asking the great man to advise me on my senior honors thesis. He later became my graduate adviser, and after that a senior colleague at Harvard. It took me a long, long time to call him Sam, even as it took me a long time to realize that he was, in some ways, a shy man. It took me no time at all--I remember the shrinking feeling in the gut very well--to know that anything I gave him to read would be examined swiftly, its weaknesses exposed bluntly, on the notion that the academic life was not about being gentle in exposing inconsistency, sloppiness, or error. It took me only a little longer to realize that I had a mentor who would push me hard, but would look after me and my interests to the end. Sam was the kind of professor who gave his students a lifetime warranty.

Sam expected you to push back, moreover, and to subject his own arguments to scrutiny no less severe. If anyone was entitled to professorial ego, it was Sam, but he was ever ready to say, "Hmf. I never thought of that before." In Sam's circle there were liberals and conservatives, and (rather more bitterly divided in some ways) adherents of different methodological schools, from the historically oriented traditionalists to the more quantitative researchers or formal modelers of the contemporary academy. He really didn't care which you were: What concerned him was whether you had something interesting and plausible to say about how the world worked.

Sam's daunting intellect played across an expressive face. A dubious assertion would elicit a pushed forward jaw, eyebrows arching up, head tilted back, the look of cool, razor-like intelligence radiating from blue eyes. It turned more than one graduate student's knees to water. But Sam's other side was a toothy, boyish grin, a roaring laugh, the kind of look that Michael Shaara caught in his fictional account of Joshua Lawrence Chamberlain--"that clean-eyed, scrubbed-brain, naive look of the happy professor." He and Nancy--whose warmth and kindness embraced all, from retired ambassador to timid graduate student--welcomed us to their homes in Boston and Martha's Vineyard. After jumping the waves at Sam's summer place, or having dinner with visiting generals and foreign diplomats at his home on Beacon Hill, some of the terror abated.