Purpose - This paper attempts to underpin the theoretical claim of the viable system model to specify the necessary and sufficient reconditions of organizations for viability. Design/methodology/approach - A number of case studies are explored. Findings - The evidence documented in the paper both corroborates the model's claim and provides evidence of its enormous diagnostic power. Originality/value - The cases documented here cover a wide range of applications, thus underlining the vast potential of the VSM. The case studies exemplify the unparalleled strength of the model as a conceptual framework for better organizational diagnosis and design, and can therefore be used for didactic purposes.