While it is true that Shatner and Nimoy have become best friends, they weren't particularly close during the three years while making TOS. After reading Gene Roddenberry's biography and Herb Solow and Robert Justman's making of Star Trek book, it is clear that during the making of Star Trek, Shatner and Nimoy didn't like each other at all.
It's not clear to me. Sure, it's well-documented that they were each very motivated for their characters to be important and successful, and they fought over lines, etc. However, can we infer from those facts that they "didn't like each other"? I can't.
Doug
It's in the official Gene Roddenberry biography. And the book written by Herb Solow and Robert Justman. I don't have them in front of me at the moment so I can't quote the exact lines and pages. But Gene, Herb and Rob all talk at various points about the problems between Nimoy and Shatner.
Some of the arguments were pretty immature. Especially about Shatner sometimes forgetting his lines, because the scripts to most episodes weren't finished while they were filming them. And lines were often being written or re written right up until the actors had to speak them. Not allowing anytime to memorize lines, especially for Shatner who always had the most.
And then there was the amount of attention that Nimoy got on set for makeup and lighting. Shatner felt that they were fawning over Nimoy and leaving him out. As well, Nimoy, because of his extra makeup requirements had to be on set earlier and leave later than everyone else. The third season episode "
The Enterprise Incident" came about partly to slightly remedy this. By having Shatner wear Vulcan ears (or in this case Romulan ears) he could see what Nimoy had to go through, though just briefly. And try something different, and get the attention he felt he was missing out on, on set.
But compared to the rest of the cast, Shatner and Nimoy weren't really that much of a problem. In fact the only person who seemed like a total professional, and nobody ever had a single problem with during the three year run was DeForest Kelley.
But after it was all said and done Shatner and Nimoy both agreed that their attitudes were pretty immature, and they have even said so in interviews. And often joke about the early days of their relationship. An exchange in the
Futurama episode "
Where No Fan Has Gone Before" sort of touches on this and spoofs how egotistical Shatner was or is perceived to be:
Nimoy: When I directed Star Trek IV, I got a good performance out of Bill because I respected him so much.
Shatner: And when I directed Star Trek V, I got a good performance out of me because I respected me so much.
So they didn't hate each other while making
TOS but they weren't particularly close. But they got better after, and are now best friends as seen in numerous interviews.