Why do some find any book very deep, others empty, others abstruse? Why, when you reread the book, do you find something overlooked every time? Why does someone understand all the shades of meaning, see the hidden between the lines, hear the music of words, feel their taste, color and smell, and someone remains deaf to them? Why does someone perceive the content of the textbook the first time, while someone needs to explain it many times? To tune in to the "wave" of the author and understand more, it takes the ability to read actively. It was for this that Mortimer Adler, an American philosopher, editor and teacher, wrote his book, who devoted his whole life to teaching people to love and understand books (later he headed the editorial board of the encyclopedia Britannica).