In a literary game of consequences, each author would write one chapter, leaving G.K. Chesterton to write a typically paradoxical prologue and Anthony Berkeley to tie up all the loose ends. In addition, each of the authors provided their own solution in a sealed envelope, all of which appeared at the end of the book, with Agatha Christie’s ingenious conclusion acknowledged at the time to be ‘enough to make the book worth buying on its own’.
As Sayers explained in the introduction to the book, "Each writer must construct his instalment with a definite solution in view—that is, he must not introduce new complications merely 'to make it more difficult' ... [E]ach writer was bound to deal faithfully with all the difficulties left for his consideration by his predecessors."
Literary significance and criticismEdit
"These members of the (London) Detection Club collaborate with skill in a piece of detection rather more tight-knit than one had a right to expect. There is enough to amuse and to stimulate detection; and the Introduction by Dorothy Sayers and supplements by critics and solvers give an insight into the writers' thoughts and modes of work."