Robert Barnard said of this spy novel that it was "The last of the thrillers, and one that slides from the unlikely to the inconceivable and finally lands up in incomprehensible muddle. Prizes should be offered to readers who can explain the ending. Concerns the youth uproar of the 'sixties, drugs, a new Aryan superman and so on, subjects of which Christie's grasp was, to say the least, uncertain (she seems to have the oddest idea of what the term 'Third World' means, for example). Collins insisted she subtitle the book 'An Extravaganza.' One can think of other descriptions."