Our story is not unusual. In your 30s and 40s, plenty of new people enter your life, through work, children’s play dates and, of course, Facebook. But actual close friends — the kind you make in college, the kind you call in a crisis — those are in shorter supply.

Friendship is a bulwark against stasis, a potential source of creativity and renewal.Practically everyone who studies friendship says this in some form or another: What makes friendship so fragile is also exactly what makes it so special. You have to continually opt in. That you choose it is what gives it its value.

* “The dynamic of friendship is almost always underestimated as a constant force in human life: a diminishing circle of friends is the first terrible diagnostic of a life in deep trouble: of overwork, of too much emphasis on a professional identity, of forgetting who will be there when our armored personalities run into the inevitable natural... See more