I think that Monster of the Week has one of the best Keeper's guides of any book. It was the first time I ever read about the GM's agenda and principles and how those can be used to set the tone, keep things moving, and guide GM choices. I also love the use of countdowns (or clocks) to control pacing. From a GM's fun perspective, the framing of the GM's job as making "moves" is very appealing to me because even though as a PbtA GM I'm not rolling the dice, I'm still playing the game not just setting the scene. MotW was also where I learned about "failing forward" and that a "miss" never means nothing happens.
I think that Monster of the Week has one of the best Keeper's guides of any book. It was the first time I ever read about the GM's agenda and principles and how those can be used to set the tone, keep things moving, and guide GM choices. I also love the use of countdowns (or clocks) to control pacing. From a GM's fun perspective, the framing of the GM's job as making "moves" is very appealing to me because even though as a PbtA GM I'm not rolling the dice, I'm still playing the game not just setting the scene. MotW was also where I learned about "failing forward" and that a "miss" never means nothing happens.