The social atmosphere in forensic hospitals and correctional institutions is crucial to their success - this "manual and more" shows how to assess the climate and identify ways of improving it. The Essen Climate Evaluation Schema (EssenCES) described here is a short, well-validated questionnaire that measures three essential facets of an institution's social atmosphere. An overview of the EssenCES is followed by detailed advice on how to administer and score it and how to interpret findings, as well as reference norms from various countries and types of institutions. The EssenCES "manual and more" is thus a highly useful tool for researchers, clinicians, and service managers working in forensic settings.