Wow. This is an amazing piece of work. The mother of a high-school killer writes letters to her husband, describing Kevin's life as she experienced it. I can't write a lot about it without getting heavy on the spoilers, but I will just say this.
When I was a few pages in I was getting a strong sense of this absence of a voice: the husband was not to be heard. But then I thought two things. First, all epistolary novels are like that to some extent; though it is possible for the letter-writer to refer to things their correspondent has written in return.
Second, it occurred to me that Shriver, by excluding the man’s voice, might have been making a point about the relative exclusion of women’s voices in literature. In other words, the way I was feeling might be akin to how Jean Rhys must have felt when she read Jane Eyre.
I don’t, now, think that she was particularly trying to do that, though the effect of the early chapters is still there.
I’ll say no more for fear of spoilers, except: highly recommended.