Andrew Glassner 
Interactive Storytelling [PDF ebook] 
Techniques for 21st Century Fiction

We are on the verge of creating an exciting new kind of interactive story form that will involve audiences as active participants. This book provides a solid foundation in the fundamentals of classical story structure and classical game structure and explains why it has been surprisingly difficult to bring these two activities together. With this foundation in place, the book presents several ideas for ways to move forward in this appealing quest. The author has a conversational and friendly style, making reading a pleasure.