Usually I avoid spin offs from television like the plague. When I was much younger, I devoured everything to do with Star Trek, and mind you, this was long before there were the films or the television series. In short, there wasn't much, so you took what you got.
This one does a great bit of storytelling about the alternate-universe Spock from the episode Mirror, Mirror
and shows how he eventually took over the Empire -- and then some. Told as a series of vignettes, it's one that is smart, and doesn't insult the reader. Very much recommended for fans of the old, Classic Trek.
For the longer review, please go here: