This is, up to now, my least favourite in the Poirot series. Of course, it's fun to read as the writing style of Christie as such is as good as ever. However, The Big Four is more of a thriller story than a real detective narrative. Afterwards, I read that it was composed of separately published short stories and that Christie herself noted ``I have been, once, in a position where I wanted to write just for the sake of money coming in and when I felt I couldn't – it is a nerve wracking feeling. [...] That was the time I had to produce that rotten book The Big Four [...]''. One can tell. :-(