Fullness of Life is a basic introduction to the Catholic understanding of salvation. It begins with a presentation of the background against which the teaching on salvation must be situated (the contemporary context of the question of salvation, the positions of other religions, the teaching of the magisterium) (chapter one), and a concise sketch on the history of soteriology (chapter two). The following chapters are a discussion of models for interpreting salvation relating to Christ's death on the cross (chapter three) and the totality of His life (chapter four). These considerations are concluded with a presentation of St. Thomas Aquinas' interpretative proposal (chapter five), which proves to be an apt way to synthesize the discussions presented earlier. The model of salvific mediation eventually turns out to be a higher-order model that allows to close the entire presentation (chapter six). The body of the text is supplemented by appendices that discuss a chosen set of particular problems related to the reflections in the corpus, that is, the "scapegoat" as a figure of Christ, the salvific function of other religions, substitution in Aquinas, and salutary suffering. The entire text ends with a selection of relevant sources. With the help of such a structure, the book proposes a basic explanation of (sometimes distorted) interpretations of sacrifice, substitution, satisfaction, divinization. It helps to bring readers from their first steps of soteriological reflection to Aquinas' synthesis and to help them to discover that - taking into account the contemporary discussions and problems - Aquinas' account can still offer a very convincing way for synthesizing soteriology. The book is addressed primarily to students of theology. However, it has been written in such a way that any Christian properly motivated to deepen their faith can benefit from reading it. And since it may serve as an aid in learning how to interpret the whole of soteriology, professional theologians may also find themselves inspired by it.