TL; DR: The best book about storytelling structure you'll ever find. A must read.
Save the Cat! The Last Book on Screenwriting You'll Ever Need describes what Hollywood considers the perfect storytelling structure for movies. And indeed, you can't see any blockbusterdeviating from that 15 beats pattern. Did someone said 'formula'?
You might argue that Hollywood's problem is obviously being too formulaic, and that's super true. But the fact that a story follows a structure shouldn't drive you away. Every medium needs to follow some rules. Graphic novels follows page design, painting canvas, and movies structures.
The point is, you don't have to follow the rules, but in order to break them, you should at least know them.
In the Save The Cat, Blake describe his structure as a breakdown of the standard 3 Act template, too vague for optimum story pacing, and divided it in 15 beats, creating what is today the most optimized screenwriting pattern.
Called the Blake Snyder Beat Sheet, and you'll find the template through a simple google search, Blake describes how, and why this structure is the best for storytelling for the big screen. He'll dig all the details, based on his own Hollywood experience, for each beat, driving you through his discoveries and stories.
The crazy thing is that it's difficult to argue with him. The structure is really optimized, and, when used properly, can give super powerful screenplays. No wonder it's the Nolan brothers favorite structure.
Like any tool, you should adapt it to your art, or transcend it by breaking the rules.
On top of it, you'll get plenty of tricks, most you can find in other scriptwriting books, but probably better packaged here.
If you're serious about writing for movies, you should definitely read this book. You won't find a more comprehensive structure analysis on the market.
Here comes a Trilogy
Save The Cat! spawned 2 sequels. Has he gone full Matrix? Let's check.
Save The Cat! Goes to the Movies is a breakdown of 50 movies from the last 35 years.
It is interesting if you plan on remaking one of the movie, or are just interested in movie studies. I found it harder to read, and less interesting than the first one, and you can easily skip it.
Save the Cat! Strikes Back is the perfect companion to the original Save the Cat!
It adresses issues and flaws that can arise in your screenplay, and show ways to make it better. May it be improving the main character arc, or making sure you haven't turned your story into a soulless formula by adjusting it for the structure, he has all the tools to help you get to the next level.
You should buy this book, which is amongst the best in the "fix my story problems" category.