You will, of course, understand that the adventures recounted in this book occurred during Mary Poppins' three previous visits to the Banks family. This is a warning to anyone expecting Mary Poppins to come for the fourth time. It cannot appear and disappear indefinitely. And besides, three is a lucky number. Those who have already read the first three books about Mary Poppins will meet not only already known characters, but will also meet new ones. And those who haven’t read it, I hope, will want to read it when they close the last page of this book.