At 76 I am old enough to have experienced the old-fashioned kind of discrimination. It happened in 1965, when I was in my second year at Harvard Law School. I was looking for a job as a summer associate, a rite of passage that generally leads to permanent employment. I remember feeling pretty confident, having ranked 40th out of 530 in my first-year grades.

I applied to the four law firms I considered the best—all “white shoe” firms in downtown New York. I arrived at each interview in my best suit, hair trimmed and shoes shined....