I've read numerous books on screenwriting, and while many are helpful, few are as approachable as "Save The Cat: The last Book on Screenwriting You'll Ever Need". Blake Snyder's style is casual and to the point. The book is filled with incredibly useful chapters thankfully devoid of fluff or or excessive wordiness.One thing to study is the "Blake Snyder Beat Sheet". It takes all the basics of structure and gives you a solid framework to start with, while at the same time being intuitive. Apply it to the next movie you watch and it'll make perfect sense.I recently earned a certificate in screenwriting from UCLA, and I recommend this book for writers of all experience levels, either as a refresher, crash course, or or supplement to what you already know.Mike Hultquist.