A while ago I read a review of another book, along the lines of "Now that I'm finished, I have no idea what it is I just read!" ... which pretty much sums up my experience here.
First, let's get the most glaring weakness out of the way. Mattison has attempted (sadly, failed in my opinion) to incorporate two time periods into one book. Unfortunately, she goes back and forth between them quite abruptly, giving this reader a severe case of mental whiplash (it might be the ebook formatting, but there have been other reviewers complaining about this as well); she would've been far better off alternating shorter chapters.
Then there are the characters. Her protagonist, Con, I had trouble believing was at all a successful attorney; when legal issues arose (regarding her mother), she seemed almost intimidated by them. I got the impression Mattison settled on her profession arbitrarily, just to give her one. In general, she seemed a weak, confused person. Her daughter Joanna seemed a whiny brat. Jerry, Joanna's dad (Con's ex), was actually likeable, along with the Brooklyn neighbor Peggy. Her mother's old friend Marlene seemed almost stereotypical to me as a villain - if there were some redeeming feature in her presence, I missed it, except for facing down Joanna at the end. I never lost the feeling that she and Gert were ... more than just friends, explaining Gert's attachment to her, though Mattison never actually goes there except for one brief reference.
Would I recommend the book? Not really, no. Would I try more of Mattison's writing. Yes, as her descriptions of New York City (Brooklyn in particular) were quite good. There's a longish section where Con and Jerry go off tracking down a Brooklyn historical feature that held my interest quite well; that part would rate three - four stars on its own. My verdict: this was an idea that just didn't transfer well from the author's head to the written page.