In "The Observer"'s issue of 15 November 1936, in a review section entitled "Supreme de Poirot", "Torquemada" (Edward Powys Mathers) wrote, "I was not the only one who thought that Poirot or his creator had gone a little off the rails in "Murder in Mesopotamia", which means that others beside myself will rejoice at Mrs Christie's brilliant come-back in "Cards on the Table". This author, unlike many who have achieved fame and success for qualities quite other than literary ones, has studied to improve in every branch of writing in each of her detective stories. The result is that, in her latest book, we note qualities of humour, composition and subtlety which we would have thought beyond the reach of the writer of "The Mysterious Affair at Styles". Of course, the gift of bamboozlement, with which Agatha Christie was born, remains, and has never been seen to better advantage than in this close, diverting and largely analytical problem. "Cards on the Table" is perhaps the most perfect of the little grey cells."