The diagnosis of brain tumours is typically based on clinical symptoms, radiological appearance and often, a histopathological diagnosis of a biopsy. Since treatment of histologically or radiologically similar tumours can vary widely according to their specific nature and patient's characteristics, accurate non-invasive diagnosing techniques are highly sought after in the neuro-oncological practice. Computational intelligence can arguably contribute to enhancing current imaging and spectroscopy-based diagnosis of brain tumours by applying heuristic methods that can learn, adapt, and evolve over time. In particular this special issue reports the state of the art in intelligent agents, security, knowledge representation, machine learning, clinical data management, and interactive user interfaces in the context of the HealthAgents project.