I was looking for something easy to read between some work-related books and grabbed Laura Lippman's The Innocents I'd bought from a thrift store earlier. I'd read one or two of Lippman's Tess Monaghan novels and thought they were pretty good. I knew this wasn't part of the series, but I knew it was a stand-alone book, and thinking I'd read it in a jiffy started to read it. (Tess Monaghan makes a short appearance, though, giving the story an extra boost.)
Instead it turned out to be a serious mainstream novel, with an episodic and a bit labyrinthine structure, with people's lives mingling with each other's lives, criss-crossing in time and place. Lippman gives hints there's something bad in the past of people she writes about, but she reveals it a bit by bit, very slowly, but enticingly. I didn't read this in a jiffy, but I still enjoyed it quite a bit. It could've been shorter, but that's just me.
Seems like this was published in the US as The Most Dangerous Thing. I found a British edition that has an alternate title. (Explains why this can't be found from Lippman's site with that title.)