The Book of the Week is the first paperback edition (with dust jacket) of The Hampdenshire Wonder by J.D. Beresford. First published in hardback in 1911, The Hampdenshire Wonder is the story of a super-intelligent child. This was an important early treatment of the question of what the next phase of human evolution will be, yet has been neglected over the years, as Beresford never realized the fame of his contemporaries H.G. Wells and Olaf Stapledon (whose 1935 classic Odd John was influenced by The Hampdenshire Wonder).
This first paperback edition of The Hampdenshire Wonder was published by Penguin Books in 1937. It was among the first one hundred mass-market paperback books ever printed, all released in England by Penguin between 1935 and 1937, all before Penguin's American counterpart Pocket Books got into the act in 1938. By my reckoning, The Hampdenshire Wonder was the first science fiction book ever published in mass-market paperback. Like all early Penguin paperbacks, The Hampdenshire Wonder lacks cover art, but makes up for that with its dust jacket. Dust jackets on paperback books are a rarity, and vintage paperbacks with intact dust jackets are always collectible.
Penguin and Pocket began to create the market for mass-market paperbacks in the late 1930's, and they took a few years to catch on. But that does not mean readers had to buy hardcover books before that. In fact, there was another inexpensive format available to readers, a format that dominated the fiction market for a half-century before being squeezed out in the 1940's and 50's by paperbacks (and comic books, for younger readers). You will see the first of many examples of that format next week.