By Lawrence Summers
The opinions expressed are his own.

September 11, 2001, was the day before classes were to start at Harvard College during my first year as Harvard president. I first heard of the planes crashing into the World Trade Center as I left a routine breakfast at the Faculty Club. Neither I nor anyone around me had full confidence about how to respond to such an event, one without precedent in our life experience. But, by midday, we had decided to hold a kind of service late that afternoon to commemorate what had happened, to try to provide reassurance to a scared community of young people.