Dorchester’s Dennis Lehane will be back in Boston next month to talk about his new novel, “Small Mercies,” which is set amid the tumult of desegregation and busing in 1974 Boston.

He will speak on Sun., March 3, from 1:30 to 3 p.m. at the Boston Public Library in Copley Square. You must register and seats are limited. Go to bpl.org and click on events to find the link.

This year is the 50th anniversary of Judge W. Arthur Garrity’s decision that ordered busing as a remedy to desegregate Boston schools. Lehane’s book is set in August, the month before the first phase of busing began.

The main character, Mary Pat Fennessy, lives in a Southie public housing community, where she grapples with her views on, and relationships with, Black people. How she was raised to think about this begins to conflict with her values and her experience of working with Black people.

At one point, she says her opposition to busing is not about prejudice and “that she’d be just as mad if her daughter was being bused to the North End or Revere (but maybe not as mad.)”

The book includes an incident of white teens chasing a Black man whose car broke down into a subway station where he is hit by a train and dies. As Chris Lovett pointed out in a Dorchester Reporter article last year, it’s likely based in part on the killing of William Atkinson at Savin Hill MBTA Station in Dorchester by white teenagers.

A large part of the novel revolves around Mary Pat trying to find out what happened to her daughter Jules and the role played by a Southie mob boss modeled after Whitey Bulger in her murder. A white police officer from Dorchester has a major and poignant role, too.  At one point, he wonders how it is that people from Dorchester and Southie were so different despite all the Irish Catholics living in the two abutting neighborhoods. I think that’s an interesting question, but Dorchester and Southie have changed a lot since 1974.

Lew Finfer is a Dorchester resident and co-chair of the Boston Desegregation and Busing Initiative.