The books centre on the magical English nanny Mary Poppins, who is blown by the East wind to Number 17 Cherry Tree Lane, London, and into the Banks' household to care for their children. Encounters with pavement-painters and shopkeepers, and various adventures ensue, until Mary Poppins abruptly leaves, i. e. , "pops out". Only the first three of the eight books feature Mary Poppins arriving and leaving. The later five books recount previously unrecorded adventures from her original three visits. As Travers explains in her introduction to Mary Poppins in the Park, "She cannot forever arrive and depart. "