Read this book in two nights, mostly skimmed the last third as it moved to a fairly predictable conclusion. A multiverse semi-thriller. Was remarking the other day that once Nolan introduced, in Interstellar, the visual of the multiverse, at the edge of the black hole, or who cares, really, that has given license to every writer and filmaker to appropriate the trope and imagine the multiverse as a series of doors. And you can go through them through some incantation or other. The OA did this really well, partly because it was hard and it might not work and it would be scary if you did it. But they too faltered (with Khatun/Baba Yaga fishing?). Anyway, this novel, Dark Matter, is basically a midwestern identity thriller (think Witness) with a little sci-fi dress-up. I needed an airplane book distraction, so it worked just fine.