xviii Introduction NavigatiNg the book We are information architects. Even though reading on paper has its rules and a certain degree of sequentiality cannot be avoided, we wanted to be able to give readers some freedom in the way the book can be browsed, which is usually the purpose of the index and table of contents, and books are usually good at this: we just decided to push the envelope a little. You will find that you can actually just jump from image to image and find out that the core ideas from the various chapters are there, easily recognizable. Then, as many other books from Morgan Kaufmann, we have small side boxes that highlight or explain some important concepts we are dealing with in the main text. We tried to give them some pace and turned them into a bookmarking or navigating system that you can use to check out the most important concepts more easily or to find your way through the book faster. oN beiNg leaN