When I was a youth I enjoyed playing interactive RPG adventure books called Fighting Fantasy Books by Ian Livingstone and Steve Jackson. I still have some of the these very creative books at home. The first one of the popular series is called The Warlock of Firetop Mountain published in 1982 by Wizard Books and it stands for the principle of ramification of literature. During these analog days I used a pencil and a dice to play the interactive adventures.
Today the Guardian published a list of 10 best interactive book apps. I think digital media is a great opportunity to develop interactive fiction and non fiction books. A nice app for the Ipad I discovered is Sherlock: Interactive Adventure developed by HAAB. If you have development expertise, or you have other recommendations or apps I should know about, please do not hesitate to comment.
Also very interesting is this Overview of the British Game Development since 1975.