The word “diagnosis” evokes associations that remind us of a doctor’s visit, troubleshooting a car, or monitoring and maintaining large technical systems. All these situations have in common that through (dia) knowledge (gnosis), the foundations for further therapy, repair, or maintenance are created. Without a precise analysis, the further work on solving the problem often remains a tiring and unsatisfactory game of trial and error. To ensure that the diagnosis is targeted and effective, this chapter presents some proven approaches in the form of questionnaires and guidelines, explained with examples. It is essential—in the context of diagnosis—to get to the core of the identified problem and uncover contradictions in the system under consideration. Such contradictions—which both condition each other and exclude each other—can arise from conflicting desires, organizational conditions, or natural scientific laws.