The only reason I found this slow going to begin with was because I'd just read a book that contained a museum filled with odd and disturbing material (i.e., Geek Love). It almost made me want to put this down and try again after a few more months had passed, but in fact, the story took a different turn.
Hoffman wrote this book because she'd been commissioned to write a journalism piece about the Triangle Shirtwaist Fire, and this was an opportunity to build a fiction tale around this, as well as write a little about her own history (specifically, her grandfathers). At times the tale unfortunately starts to sound as if it's a lesson about both the importance of unionization as well as the perils of greed, but Hoffman is a good writer and knows to veer away from these problems at her first opportunity.
The most fascinating aspect of the novel, for me, was the swimming. In both the cold, the dark and the dangerous waters of the Hudson. What kind of person is willing to do this? I would suspect a very rare one, and it was clear she was also telling a tale with a large element of fantasy to it. Of course, the novel is set at a time in New York City's history when the skyscrapers did not rule the land, so having that as a backdrop created its own level of fantasy, or at least disbelief in that ancient state.
As usual for Hoffman, this book has a love story at its midst, and it is absolutely the glue that binds the book as well as the beautiful heart of it.