As we approach the seventieth anniversary of the first appearance of Mary Poppins, interest in P. L. Travers' most famous creation is still strong and the time is right for a reassessment of a work that is rich in meaning for child and adult readers alike. This book attempts to analyse some of the reasons behind the longevity and the ongoing appeal of the Mary Poppins material, with particular reference to intertextuality and the presence of what Freud described as "the uncanny". By comparing and contrasting the Mary Poppins material with previous texts, it can be seen that Travers has been drawing, consciously and subconsciously, on the great myths and archetypes of the collective human storytelling experience. The idea therefore emerges that the Mary Poppins stories touch on some fundamental aspect of the psyche - an aspect where the symbiosis of security and fear, the familiar and the unknown, are made manifest to the reader, whether as children finding their way into adulthood or as adults recalling their beginnings.