If you're looking for a quick read that you can finish in an hour to two hours and still get as much from it as possible, The Chasm is for you. Randy Alcorn paints a vivid allegory to various aspects of the Christian faith while still staying focused on one plotline of the story.
Many will compare this book to Pilgrim's Progress. I would agree, except I got much more from this then I ever got from Pilgrim's Progress.
The book itself doesn't really give you any base to go from starting out, but it really isn't necessary. There's plenty of references to the real world, while it never really goes into the real world. Even though many will not easily grasp the concept of storytelling this book gives, everyone should read it through and through.
It's a short, precise, 110 page book that relates the troubles of life, the sinful state of man, and the ultimate price that had to be paid as well as the life to be lived after. It's a rock solid allegory that I highly recommend.