I'm very much into the topic of film making and, of course, into Star Trek, though generally more the spinoffs than the original series.
This proofed to be the perfect mixture of behind the scenes information and personal anecdotes, told in a mostly humorous way but still with appropriate seriousness in the right places.
It tells the story of making Star Trek, not only from Shatner's perspective, but through various interviews from a lot of cast and crew members, so I felt like I'm getting a full picture of what was going on, beginning from the very start. Shatner is also willing to admit some of his flaws, which I really want to give him credit for.
If you don't already feel you know everything about TOS, this is probably a must for fans of the series.