After "Bach, Escher, Gödel", Douglas Hofstadter delivers another lighthouse for a generation. A generation of humans that will probably be confronted with other thinking entities and that will not be able to forgo the question 'why we are thinking the way we are thinking'. The biggest quality of this book is to make out of the simplest question a challenging problem, as indeed what we perceive to understand on the surface is not what we understand in the labyrinth of our mind. For readers who want to grasp that the meaning of each word is more of a cloud and have the energy to turn every word many times around to view its different angles, this will be a book to enjoy. It will take you on a journey on long winding roads, with heights and lows and it will be tiresome but this is probably the only way to envisage the complete scenery and be satisfied of your accomplishment at the end of the story.