I had just seen the movie, so I knew what the big plot twist was. In that sense, I was reading it less for the story, and more to get a feel for how Christie wrote. Turns out, she writes well – very clear, with a minimum of fluff. And perhaps unsurprising given the context of her hero, there’s never a small detail that doesn’t matter. When someone mentions a detail that seems extraneous, you can bet it’s a clue that Poirot picked up on and will come back to later.