As a man who fled from graduate school only a couple of semesters in, and as someone who has spent perhaps too much time worrying about past mistakes, I fell right into this story of a graduate student in Physics who builds a machine that allows him to look into alternate realities where he made different choices.
As he peeks in at each life, he sees some of the mistakes he’s made in his past, but Kritzer deftly avoids making him mawkish at the opportunities he’s missed. However, there’s a cost to using the machine, which our protagonist eventually realizes, and a moment where I wonder if the professor whose notes he used to build the machine maybe wasn’t as ignorant of it as he seemed.
The Moment of Truth is a good one, and while Kritzer could easily have built a novel around this concept, I think her choice of where to end and how to do it was the best option. She has, however, left a door open for a linked story if she ever chooses to pick up this story again.