Increasingly, ecological assessments of entire companies are being conducted today. The author explains in this book how such eco-ratings are carried out and what significant weaknesses they have. Based on this analysis, he presents in clear and understandable language how evaluation methods can be developed using Fuzzy Logic that also take into account complementary and conflicting relationships between individual criteria. This is fundamentally important for the correct interpretation of ecological information and thus for an accurate ecology-oriented assessment of companies in a world characterized by increasing interconnectedness. The evaluation method presented can also be applied to non-ecological contexts.