Diagnoses have always been controversial in educational contexts: on one hand, they serve as a basis for professionally justified decisions, while on the other hand, they are criticized as categorizations that do not do justice to individual cases. The contributors to this volume address the tension between categorization and understanding individual cases with regard to various educational fields of action. The authors critically examine the tradition and concept of diagnosis and discuss different diagnostic approaches using case examples related to different educational practice areas. They present psychoanalytical-pedagogical diagnostics as a dialogical approach that takes into account not only the current interaction but also the biography and life world of the clients. They emphasize that this type of diagnostics involves inclusion.