Book excerpt: When did Christians begin to address environmental questions? What can be learned from these pioneering thinkers? This study reveals that between 1910 and 1954 many theologians called for responsibility towards nature. The focal point is the work of Joseph Sittler (1904-1987), an American Lutheran and ecumenical theologian. The role of these early ecotheologians is discussed in relation to environmental history and education. The findings show that ecotheology was not as strongly separated from other environmentalism as it was after the 1960s. (Series: Studies in Religion and the Environment / Studien zur Religion und Umwelt, Vol. 12) [Subject: Religious Studies, Environmental Studies, Ecotheology, Joseph Sittler]