All of the episodes in TOS and TNG have a summary and most (>95%) have some behind-the-scenes arcana. There is surprisingly little "[actor] was also in [other feature]" type stuff, but rather juicier background on all of the writing and directorial changes.
While the honesty in stating "Star Trek 1 was terrible" is refreshing, it seems like the authors dwell more on the "problem" aspects of the show. For example, in discussing the episode "City on the Edge of Forever," the authors spend a much longer amount of time on the Harlon Ellison saga (Ellison writes the story, it gets butchered into an episode, both win awards, Roddenbery and Ellison at odds over credit).
The result is a less-than-flattering portrayal of Gene Roddenbery. (To be fair, I came away a greater awareness of and respect for Gene Coon and Rick Berman.)
Overall, a worthy read for the die-hardest Trekker.