But it also teaches you a technique to develop memory (helpful for students but also for all persons exercising a profession for which memory is important), the mental calling that many people call display (although for the author, this is not entirely the same thing), reshaping the face and body in a more aesthetic, and many other helpful tips.
In addition, you also Zener cards at the end of the book, card cutting preferably with a small sharp scissors to avoid damaging the cards, or the book. It is unfortunate that these cards are not in a small box, already cut. Zener cards allow you to test your ESP.