I think I have read most of the decent screenwriting books available and this one is by far the best value for money/time/effort. It is not overridden with theory but it manages to present a simple and easy-to-follow model, supported by plenty of examples. There is no magic – it all boils down to what the story of your characters is and who they are faced against (someone/something external or themselves, for example). I read it in one day and it answered many of my questions and I am sure I will read it again and again. If you want to read on this topic or if you are writing scripts (like me) – this is the first book you should buy.