[Anamnesis: a diagnostic passe-partout]

There is universal consensus that the anamnesis is a fundamental and irreplaceable phase both for the formulation of the diagnosis and for establishing the correct physician-patient relation. In a high percentage of cases the diagnostic hypothesis formulated during the history-taking is successively confirmed. The analysis of the structure of the anamnesis has demonstrated to realize a cognitive approach of phenomenological type. This kind of approach fits with the structure of illness because of its dynamic aspect. That is the reason why it represents an indispensable diagnostic key.