The term that best describes this book is clever, and I mean that both as a serious testament to the intricacies of the novel as well as the slight damnation that always comes from faint praise.
The novel's conceit is very clever and I'm ashamed it took me even five minutes to figure out what Horn was doing. The storyline was handled well; it refuses to follow its Biblical antecedents exactly while still retaining the flavor of the story. And the jumps back to historical characters were appealing.
Having said that, this book felt both a bit too neatly constructed and a bit like it failed to fit together. The contemporary (more or less) story had very obvious connections with the historical narratives, but fewer deeper level connections. Other than some name dropping and thoughts about siblings, it was difficult to get them to speak to one another. It felt like a history lesson for those unfamiliar with the Cairo Genizah was inserted into the story simply because the author was worried that her readers might not be familiar with the Cairo Genizah and she just had to tell us about it. To be fair, the Cairo Genizah is amazing! But there are plenty of amazing things that need a bit more justification before they get prime billing in a novel. And the main narrative eclipsed the characters, all of whom seemed like they could be really interesting, but Horn just breezed past them.
However, coming off of a week where I spent some time complaining about how its so much harder to write Jewish fantasy literature when the background of contemporary culture is Christian, there was something delightful about reading a book and having the references refer to my culture and rely on my shared knowledge base. Naming the software that archives one's life "Genizah" just made me happy and the book goes on from there.
The ending, for all that it failed to wrap up the multiple narratives in the way I wanted, did succeed in pulling together the main narrative in a manner that seems more and more right as I think on it.