So this is a pretty straightforward time travel story, meant to use time travel as a way to talk about our present. Which it does, very effectively. The main point of the book is a feminist vs. misogynist time travel edit-the-past war, and it stays logically true to what time travel would accomplish, but with a very interesting twist that in this telling, everyone has known through most of human history that time travel is possible. The premise is a side note to the main story, but brings up some interesting points Newitz kind of throws in along the way. The time travel machines no longer have an interface--worn away over geologic time--but are usable anyway by tapping on the rocks they appear to be. Travelers have gone back far enough to see the interface, and it has lights and buttons. Yet there is a discussion about whether they are made or a natural phenomenon. It seems obvious that they are made, but should it be? I think if I were living with something like this I would entertain the natural hypothesis, without any other evidence of other intelligence involvement. It's a lot like Intelligent Design.
The main story is a very 201- telling of a time edit battle, which serves as a platform to talk about feminism, lesbianism, and the lengths one can go to in defending an idea. It ticks all the boxes, from White Supremacy to moralism to abusive fathers. It's well done, but been done. The plot twists are worthy ones. A self-conscious time travel story is rarely explored territory--most of the others I know of are one-off events or secret societies. One very large exception would be the Terminator series, where it's invented and seems to be generally known about at the end of the future human-AI war. So overall, I'm glad I read it.