Like many other books, this book is about a journey. But unlike other books, the destination of the journey is the point where the parallel lines meet. The narrator is locked inside the book. The only way he can get out of it is by persuading one of the other characters in the book to finish off the writing process for him. But before he can do this, he has to make a journey.
On his travels, there are a number of waypoints where he must stop and collect materials which are pasted into the book. When the book is completed, he can leave the book by delivering it to the individual whom he will meet at the point where the parallel lines meet.
This journey, which is accomplished across his lifetime, takes him from the birth of Christ to the near future, with the author bending time by complex double time schemes, riddles and mathematical formulae. Every waypoint appears incredible at first, but we are in the world of weaving narrative into fiction but not fantasy. Every one of the waypoints is historical fact.
There is no trickery. The narrator does indeed take us to the point where the parallel lines meet. It had been staring at us in the face all along.