By publication date, Peter Duck is the third book in the series, but the story is supposed to be one created by the Swallows and Amazons while staying on a Norfolk wherry with Captain Flint in the winter between the first two books. Two early chapters describing this creation process were written by Arthur Ransome before he started Swallowdale. This opening was discarded from the final version of the book when it was published after Swallowdale. However, Peter Duck is mentioned in Swallowdale as Titty's imaginary friend from a story made up by the Swallows and Amazons.
Read more about this topic: Peter Duck