War and peace are the topics of the present book. No one will gainsay the assertion that peace is a vital value today, and that war is to be avoided since it is one of the most undesirable states of affairs. Therefore, the current book will address mainly the problem of war and aggression, and the possibility to live in peace. The dichotomy war-peace will be analyzed, including the problem of aggression and violence. We will begin our analysis with the problem of aggression, and we will go on with the problem of war then. The book will contain moral, psychological, philosophical and religious analysis. It will employ philosophical as well as Christian arguments and theses to analyze the problem. This still does not mean that the book will not have any value for the reader not interested in Christianity. Our analysis will demonstrate clearly that peace has many forms and could be defined in various ways; hence, the Christian conception of peace is one of them, but it will be shown that this conception meets the criteria set by common sense. Peace can be defined in geopolitical, in psychological, in moral context as well. Still, the Christian interpretation should convince the reader. It will be shown that we can have true peace only in God. Peace in the way we usually envisage it is not achievable on earth. The conception of the eternal peace is a utopia, although it is good to have hope that such peace could exist. But hope is one thing, and reality- completely different thing. We will show that it is possible to reduce military tension and conflicts in the world, but still, this will not lead to absolute peace.