Although I have to say, given all the turmoil the book describes, it's always amazing to rewatch certain episodes again and see just how smooth and confident the final product almost always ended up being-- especially compared to the first two seasons of TNG, where they were also having behind the scenes problems and many eps come across as poorly written or slapped together as a result.
I was surprised to discover that Enemy Within
was the very first time DeForest Kelly performed as McCoy. Watching the episode, it's as if they'd all known each other for years. I guess that's ACTinggg!
Also that, De's first week on set involved Evil Kirk grabbing him by the head, yanking him almost off his feet and demanding brandy.