**1. Introduction**

Multidisciplinary and ecumenical ecotheology is a science that analyzes in unity the direct determination of the existence and survival of living beings and their communities (including human society), their influencing factors (e.g., their environmental limitations, as causa efficiens), and their final determination ("ultimate concern" as causa finalis, which includes its origin, purpose, destiny, and meaning). Methodologically, it cannot exclude the possibilities of distanced, checking cognition and participatory cognition (because it needs full information), but it ensures the highest possible reliability of knowledge by applying all the possibilities of testing. As an applied science, it thus becomes suitable for overcoming the global ecological crisis and establishing a sustainable society. The aim of this chapter is to summarize the current situation in this field.

Ecotheology, including human ecology, is an interdisciplinary science that studies ecological phenomena using theological methods and approaches, i.e., it is part of ecology. On the other hand, however, it is an interdisciplinary science (belonging to theology) that interprets transcendent reality (which is reflected by the content of faith) in the context of ecological systems, and therefore it requires the cooperation of experts of both fields.

As an applied science, ecotheology is the application of theological methods in order to study the consequences of human action from the perspective of contemporary ecology. It strives to achieve that the principles of theological ethics (as well as the motivating power of faith and the communities and the institutional system of religious practice) can ensure, taking effect on human action, the harmonious functioning as well as the maintenance and fulfillment of the self-identity of the biosphere (and that of human society as an integral part of the biosphere) (according to Ituma [1], "the nature balance"). We consider it important to supplement the definition by Ituma because living systems, especially the biosphere, are usually not in the state of equilibrium; balance of nature is a term used in the previous ecological literature. Care for creation as the practical aspect of ecotheology aims to overcome the global ecological crisis and build a sustainable society for humanity.
