Triumphs of Experience: The Men of the Harvard Grant Study

George Valliant: “Happiness is love. Full stop.”

Dense, but the longest longitudinal study of human development ever undertaken offers some welcome news for aging!

You can also get a good summary of the findings here.

My husband cites this study every year in his birthday party speech. (Rec: after he blows out the candles, I always say, "would you care to say a few words?" This only works on people you know might like to say a few words...)