Arthur Ransome was forty-six when Swallows and Amazons was published in 1930. He was at a turning point in a career as a journalist in which he had covered many important stories, most notably the Russian Revolution. He had been publishing books since he was twenty on subjects as diverse as narrative technique, Oscar Wilde, cruising on the Baltic, and fishing. His friend and employer, the editor of the Manchester Guardian, offered him a salaried job with possible future advancement. Ransome turned the offer down to try writing the book that became Swallows and Amazons, a different sort of book for him, a children's book unlike others being written at that time. The experiment worked. Swallows and Amazons was widely reviewed and well received. Before the year was over it had sold 1,656 copies, and the publisher and the public wanted a sequel.

In the next seventeen years Arthur Ransome...