J. Brian Charles writes: “One day in June, the employees of Enoch Pratt Free Library gathered online to learn something new: how to de-escalate conflict, mediate grief, and help people feel better about themselves. That session was part of an experimental effort by Baltimore leaders, who hope to enlist city agencies, starting with the library, to answer a big question: How does a city that has suffered trauma for decades, including over 190 homicides just this year, begin to heal?”