This review will be the definition of spoiler free, come see us June 1 to talk details.
I am, as they say, perplexed by this book. It was like a roller coaster ride. At the beginning, I felt like this:

There was a great wide world of story ahead and it was all for me. Historians! In the near future! Using the scientific method and time travel!
But then, I spent a lot of time waiting for thins to start happening.

And that was not the most pleasant experience, really. I went the audio route for this one, since I knew I would be under a bit of a time crunch and I could listen at 1.25-1.5 speed depending and that would help. It did, but listening to all the pieces be set up on the board while knowing that there was still 20+ hours of audio left me wondering what all the fuss was about, because you good people had already started rolling in the 4 and 5 star reviews.
And then things got going, and I understood.

There are so many layers, so much context, so much world building built it that you have to wait, and then you start to have fun, but there’s also that moment when the doom is coming (which by the way the blurb for the book spoiled for me, not that it isn’t telegraphed a mile away) that I actively stopped reading because I didn’t want to read what I knew was about to happen. It was too much, both for the characters and for me.
This book lives and dies by its characters, and they are good. I look forward to hearing what everyone has to think.