In this book, "Ibn Sina" talks about the human psyche and proves the logical and mental proofs that it differs from the body in the essence, and through these proofs, "Ibn Sina" finds a psychological state in which the soul completely overlooks everything that is physical; She only feels her own entity. And it proves that the soul remains after the annihilation of the body, and then clarifies the levels of souls between happiness and naughty after the paradox of the soul. The philosopher concludes the brief, adequate message by mentioning the three worlds: the world of the mind, the world of the soul, and the world of the body, in a simple and eloquent manner at the same time.