Aspects of the analysis of a 5-year-old boy with a fear of dogs were presented to demonstrate the development of a preneurotic fear into a classical phobia. I discussed some ways of distinguishing between fears and phobias and argued that while the external appearance of a symptom may remain essentially the same, the underlying structure of it may change. The persistence of the plastic figure of a dog as an object of fear was seen as a formal kind of structural persistence, while development of ego functioning proceeded. Many possible origins to the patient's fear of dogs were considered, though delayed language development made a significant contribution. The fear and possibly the phobia also figured in Larry's efforts to maintain a narcissistic equilibrium made precarious by the peculiarities of his early relationship to his mother. In Larry's case, an otherwise poor prognosis was tempered by the fact that he had analysis in childhood and that he was largely restored to the path of further development.