The snow has finally ended, spring break is behind us, and major-league baseball is underway. That means the 2013-14 college year is entering the home stretch, and at Harvard Law School in Cambridge, Mass., a legendary law professor will soon deliver his final lecture.

After 50 years with the same employer, Alan Dershowitz is nearing retirement. By his count, he's had 10,000 students, and they include some of the leaders of the world, although not one who, despite becoming editor of the law review, was denied access to his enrollment. Dershowitz told me recently he will always remember fondly using the Socratic method in criminal law classes, where, in any given 90-minute lecture, he'd call on about 40 students out of 150 assembled.

"No answer is right," he said. "I'd go from student to student. I knew my students very well and knew what their positions essentially would be so I knew who to call on to get a good, provocative discussion going."

Judging from those whom he's instructed over the years, he had a wealth of choices. Recently, I asked him for a sound bite on some of the better known.

Former presidential adviser David Gergen: "Very quiet, very quiet. Not memorable in the classroom, but outside the classroom, when we would talk, he clearly was a leader. You could see that."

Former U.S. Sen. Elizabeth Dole (R., N.C.): "She was very talkative, and she was in a class of practically all women because in those days family law was called women's law because women were thought to be only suited for the soft stuff. She was not soft at all. She was brilliant."

Jim Cramer, host of Mad Money on CNBC: "Jim didn't come to class all that often. He was buying and selling stocks. . . . You know, his answering machine when he was my research assistant had stock tips."

Former New York Gov. Eliot Spitzer, who resigned his office over a prostitution scandal: "So terrific a research assistant! Maybe everything that happened to him since was my fault because one day I said to him, 'Eliot, you're working too hard. Go out and have some fun.'"

U.S. Sen. Ted Cruz (R., Texas): "Off-the-charts brilliant. And you know, liberals make the terrible mistake, including some of my friends and colleagues, of thinking that all conservatives are dumb. And I think one of the reasons that conservatives have been beating liberals in the courts and in public debates is because we underestimate them. Never underestimate Ted Cruz. He is off-the-chart brilliant. I don't agree with his politics."

There was also the Harvard Law student who couldn't get into a Dershowitz class despite multiple attempts: Barack Obama.

"Twice because the computer kept him out," Dershowitz said. "It wasn't my fault."

I asked Dershowitz if his memory extended to the not-so-famous he has instructed. He assured me that eventual fame has nothing to do with his uncanny memory and instead credited his own educational mentor.

"Very early on I get to know all of my students and really get to know their positions," he said. "I learned that from a professor at Brooklyn College named Samuel Konefsky, who is blind, and within three or four days he could recognize any student in the class by their voice. He would call on students by name as long as you just said, 'Professor, I have a point.' You couldn't raise your hand, obviously, because he couldn't see. But as soon as you started talking he would say, 'All right, Dershowitz, tell me why this...' He was amazing."

Of course, Dershowitz's career has transcended the classroom. While maintaining his teaching responsibilities at Harvard, he has also represented high-profile clients, including Leona Helmsley, O.J. Simpson, Claus Von Bulow, and Pervez Musharraf. Not bad for a guy from Borough Park, N.Y., who was the first in his family to go to college, and who himself had a "67" average in high school.

"I failed physics," he said. "I failed math in high school in my upper senior, first semester, and then I got straight A's in physics and math in Brooklyn College."

What changed? "I didn't have rabbis teaching me anymore," he told me. "I went to Yeshiva and I didn't take to the kind of religious dictation of what to think, and I had a bad reputation and it followed me, and then, when I went to college, I had a good reputation that followed me, and then through law school."

Dershowitz has just published an autobiography, Taking the Stand: My Life in the Law. He told me the combination of the memoir and the end of this chapter in his life at Harvard has him feeling sentimental.

"I am getting letters from my former students telling me how much they'll miss me and how other students will miss me," he said. "It's a difficult transition, but, you know, I think of it as moving forward. I am not retiring from anything, I'm just changing careers. I'm going to be doing more writing, probably more litigating and more speaking. The only thing I'm not going to be doing is teaching, but I'll miss that. Also, any time I miss it too much, I have the opportunity to go back and teach a freshman seminar or a course somewhere else. So I am dealing with it, but it's nostalgic."

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