This book combines a few different things. First, the events of Lattimer and those leading up to it. Next, a detailed history of public remembrance. There is a section on archaeology of the Lattimer site. And lastly, what's happened in the region since (and how it might relate).
The most interesting part to me (already very familiar with most pieces of the book) is that after the massacre, no one spoke about it for generations. This mirrors what happened with the Molly Maguires. Any tie to the events was good for automatic blacklisting and eviction in the company-dominated era. Families of the slain didn't pass down the story. People who survived the massacre were forced out of the region (many returning penniless to Eastern Europe). A school teacher who cared for the wounded was blacklisted from teaching, and a coal baron who donated to the widows' and orphans' fund was shunned. Multiple attempts to create a momument, even one placed in another town, were shut down. It wasn't until the 1970s and the passing of that generation that people could get traction in public remembrance. And still there is (some) pushback today.
The book also does a great 101 on the field of public memory. I knew little about that and it was great framing for the story itself. That framing has to do a lot of work because some of the chapters have no real narrative from the author. I wish they did. There's also a decent intro to archeology including the inside-the-field-view of how archaeology relates to memory and public power.
Most fun fact—Cesar Chavez spoke at the Lattimer memorial! And all the state/local union heads gave him props, calling the farm workers' movement the modern day Lattimer strike.