By the second semester of my freshman year at Harvard, I had started going to classes I wasn’t signed up for, and had pretty much stopped going to any of the classes I was signed up for – except for an introduction to economics class called “Ec 10.” I was fascinated by the subject, and the professor was excellent.Mr. Gates does not say who the professor was. And since this predates my time at Harvard by about a decade, I don't know. Perhaps Otto Eckstein, who taught the course for many years.
Update: Mystery solved. Otto was indeed the head professor, but Mr. Gates was probably referring to his section leader Robby Moore, who is now at Occidental College. Professor Moore emails me:
Hi Professor Mankiw -- I was reading your blog, and just wanted to let you know that I was the teaching fellow who had Bill Gates in my Ec. 10 section. (I actually sat next to you at the memorial service for our friend, Chip Case). In any event, it was the Currier House section that met up in Radcliffe Yard, and the academic year was 1974-75. Steve Ballmer was also in the section of about 25 students. (I am sure it was the fall semester since Bill Gates dropped out of Harvard after the micro portion of the course and I believe Bill Gates was a sophomore at the time.) Anyway, when he did come to class, which wasn't actually all that often if truth be told, he was quite argumentative, which is why I remembered him.. In fact, when I presented the standard theory of how a monopoly maximizes profits, and drew the standard diagram with the profits box at that Q where MR = MC, he jumped right up at the end of class and declared, "this theory is all wrong".......he drew a new diagram but with a different AC curve and his showed more profits at a Q where MR didn't equal MC. I tried to explain to him that you couldn't just draw in any old AC curve.......it had to be consistent with the MC curve, and the profit box had to be the biggest where MC = MR, but I'm pretty sure he felt his analysis was better. (In any event, that's my absolutely true Bill Gates Ec. 10 story.)
The rest is history.......I became a lowly Head Section Leader of Ec. 10 and created the first Readings/Workbook for the course, with all the course wide problem sets, past exams, and solutions, etc., and he started Microsoft.