One question which must be asked when reading such a rich and complex book as that by Daniel Stern, with an introduction by Massimo Ammaniti, is what is the Self and if it agrees with some of the proposed definitions. Stern says that there is no agreement about what the Self is, even if we look to those authors who have defined it as an aspect of the personality which characterizes the individual from the beginning of his life.

Stern's research is based on a child's subjective knowledge of the world from the time of birth. But “because we cannot know the subjective world that infants inhabit” - he writes with typical English understatement - “we must invent it. This book is such an invention”.

One basic assumption of Stern's work is that in the newborn child there exists a preverbal sense of the Self, which precedes the development of language and reflexive consciousness or consciousness of Self. Such is the sense of being able to act, of physical existence, of temporal continuity,