Capital, in the 21st century, has a bad rap. Many say that because it is the source of “passive income,” it does nothing but pad the pockets of the idle rich, driving a wedge between the haves and the have-nots. It’s helpful, then, to be reminded that capital in all its forms is the source of human betterment. Capital is the accumulated stock of stuff (financial assets, physical equipment, human knowhow, even social connections) that helps us make and do more stuff. So policies that drain capital from a community or discourage its formation in the first place are likely to leave a trail of destruction. This is the central lesson of Stephen J.K. Walters’ Boom Towns: Restoring the Urban American Dream.