Most reviews at the time of publication were positive, referring to "the brilliance of the whole conception", and remarking that "never has his [Poirot's] mighty brain functioned more brilliantly". Another considered this novel to be "a major Christie" and stated that "the rules were not made for Agatha Christie." One reviewer analysed the novel in some detail, considering this and recent novels to have too much of a pattern in the plot and felt that Poirot was "becoming too much of a colourless expert." A later review by Barnard was terse, "Magnificently clued."