The twelve chapters of the story were each written by a different author, in the following sequence: Canon Victor Whitechurch, G. D. H. Cole and Margaret Cole, Henry Wade, Agatha Christie, John Rhode, Milward Kennedy, Dorothy L. Sayers, Ronald Knox, Freeman Wills Crofts, Edgar Jepson, Clemence Dane and Anthony Berkeley.

In addition, each of the authors provided their own solution in a sealed envelope, all of which appeared at the end of the book.

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."

Notable crime fiction critic Jacques Barzun noted:- 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.