By the end of the 1920s, public libraries in Britain and the US were well established, paid for by wealthy railroad and steel tycoons such as Andrew Carnegie. So, publishers competed with libraries by issuing cheap editions of popular books and marketing them cleverly.
Book Clubs began: the Book Of The Month Club in 1926, The Detective Story Club, and The Unicorn Mystery Book Club in England, and in the US: Doubleday's Crime Club, Simon and Schuster's Inner Sanctum Novels, Lippencott's Mainline Mysteries, Dodd Mead's Red Badge Novels, Dutton's Mystery of the Month, and some others. Most had a trademark and a gimmick.
One gimmick was the 'sealed mystery', where the last chapter was sealed with an onionskin wrapper. If you returned the book with the wrapper uncut (presumably because you solved the mystery without needing to see it), you'd get a refund.
Another gimmick: contests. Publishers regularly held contests for stories, and Dodd Mead regularly advertised 'the 8 point test' for detective stories, a list of 'rules of the game' (some of which you may recall from the first entry in this blog series). The contests generated a lot of junk, and publishers published a lot of it, but it also generated Ellery Queen (more on Queen another day).
Serious writers of this "Golden Age" between the wars such as Agatha Christie and Dorothy Sayers worked hard to avoid the triteness and shoddiness of pulp fiction (that is, the cheap and hastily-written dime-novel fiction that appealed to barely-educated factory workers). Yet at the same time they had little patience for the so-called 'highbrow' literature that was in fashion: the experimental modernism of James Joyce, DH Lawrence, William Faulkner and the like who were gaining recognition with their interest in experimental language and symbolism and point-of-view and time-shifting.
The reaction against both 'popular' fiction and literary modernism drove Golden Age writers to an emphasis on careful plot construction, avoiding the shallow plots of pop fiction, and the avoidance of plot altogether by modernists. This meant an emphasis on the puzzle aspect. This was coupled to the rising popularity of newspaper puzzles like acrostics and the new invention of the crossword. Dorothy Sayers, as early as 1928, believed people would tire of the puzzle-solving and become able to predict the outcome too easily. Even so, mysteries became a profitable form of middlebrow entertainment, the 'classic whodunnits' we still celebrate, with 3 distinguishing qualities: purity of language, an expanded form, and 'fair play' (where the detective is still more clever than the reader).
We'll consider these qualities next time.