We all experience phobias of a mild or severe kind, crystallising our fears and aversive behaviour around a particular object or situation. Certain typical phobias may be regarded as a normal part of childhood - fear of the dark, of wild animals, of intruders. But the experience of phobia also contains something intensely irrational - why such overwhelming fear at the sight of a feather or the thought of crossing a bridge? It is around this perplexing core that a psychoanalytic explanation reveals the hidden causes of our fears.