Robert Putnam, Bowling Alone: The Collapse and Revival of American Community (2000)

For a tutorial on social capital, I've had the chance to reread this modern classic. What a joy! Bowling sets the standard for how to do social scientific research. Putnam has a knack for writing in a very accessible way, for finding all sorts of relevant data, and for humanizing the data with stories. Published 25 years ago, it's fascinating to see how he discerned trends that have only gotten worse - for example, the crisis in mental health, especially among the young (when I read Jonathan Haidt's book The Anxious Generation, I assumed that this crisis had started around 2010 - but Putnam points out that it goes back decades earlier). And of course, the collapse of community of his subtitle has now morphed into disastrous polarization. Putnam is one of my heroes.