A treatise on knowing the rational soul and its conditions

This is a treatise written by the inimitable scholar Ibn Sina in psychology, and it consists of three chapters:
Chapter One: On proving that the essence of the soul is different from the essence of the body.
Chapter Two: On the survival of the soul after the annihilation of the body.
Chapter Three: On the levels of happiness and misery of souls after the soul separates from the body.
Then he added a conclusion to it in which he dealt with the three worlds, which are the world of the mind, the world of the soul, and the world of the body, and the order of existence from the beginning of the First Reality to the highest levels of existence according to the order descended from Him Almighty.