What is silence? It is more difficult that it might seem to give an exhaustive definition of it in one sentence. Sara Maitland's “A Book of Silence” is an abundant source of reflection on various kinds of silence. It emerges from the author's own experiences and from those of other writers on whom she draws. Maitland's book, along with some of her literary and scientific sources which she refers to, constitutes the basis for the considerations contained in this article, the aim of which is to draw the reader's attention to the fact that silence is a relative phenomenon and that physical silence, understood as a lack of or muting of audible sounds, can be perceived by an individual either positively or negatively, depending on the circumstances in which the silence is experienced. Additionally, the way in which it is perceived can seriously affect a person's health and well-being and, in extreme cases, it may even decide someone's life.