Our barista, our mechanic, our coworker--they populate our days, but we often take them for granted. Yet these are the people who bring novelty and information into our lives, allow us to exercise different parts of ourselves, and open us up to new opportunities. In their unprecedented examination of people on the periphery, psychologist Karen Fingerman, who coined the term "consequential strangers," collaborates with journalist Melinda Blau to expand...