In a column today on the famous Harvard Study of Adult Development , which has followed the paths of a group of graduates from college to old age, David Brooks quotes lead researcher George Vaillant's conclusion about what matters in life: "Happiness is love. Full Stop." It's a somewhat odd conclusion since Vaillant has had three marriages (two to the same woman), and long periods of estrangement from his children. Maybe he knows how important love is because he understands how difficult finding and maintaining it can be. But I hope this is not the single message that filters out now that the original study subjects have or are coming to the point at which their files are closed. Vaillant may conclude love is the secret, but he has had a long, distinguished, fascinating career that must have helped carry him through the times when love failed. Isn't that one of the lessons of the Elizabeth Edwards saga? Yes, love is essential, but it can't be all.