What an interesting and fun experiment this must have been for the members of the Detection Club to write a mystery - in full compliance with club rules - where one author built on the previous chapters but without having a collective idea about what the plot should be.
As much as I loved seeing each author bringing their individual style to the project, the overall product left me stranded after a few chapters - by the time Ronald Knox summarised all of the clues the preceding chapters had presented to the reader I was lost. After Knox had finished with his list, I had largely lost interest.
However, the solutions that the authors had included in the appendix (not the actual solution to the mystery but the individual solutions that each of the authors predicted) made up for the struggle to finish the book.
And I have to say, Dame Agatha's chapter and solution stole the show for me. She clearly had fun writing her parts for this project and clearly did not take herself seriously in this at all. It was so much fun to watch this.