Curtain by Agatha Christie

This is one of the great Poirot books. I like it very much: it's a bit sad but very interesting and fascinating. It's Poirot's last case before he dies.
Poirot calls Hastings back at Styles Court, where they met so long ago and where their "hunting together" started. Poirot is old and weak, but his brain cells are as ever. He's there because a misterious murderer is there and Poirot knows who he is. What Poirot wants is to save his latest victim, if possible. Before the end of the book there will be an "accidental" injury, two suicides and a heart attack... then a letter will explain everything, same trick used in "and then there were none".
I think this book is fascinating, and in it there are Agatha's tough thoughts that we've already encountered in many of her books.
Spoilers, in case you care. I liked the idea of this man who in a way is a murderer but he never actually killed anyone. A cruel man, who would simply talk to mark other people's fate. He's described as having a gift for persuasion, he knows his characters, knows how to provoke a crisis. He convinced Luttrell that his wife was humiliating him too much and he caused him to shoot her, but she didn't die, probably because the husband didn't want her dead, he actually loved her, although sometimes she was a lot to take. It was cute to see him after she woke up and he was like "she wants to see me??" and he hurried to her room...
Norton also caused Hastings to almost become a murderer!!! This was Christie's brilliant touch, because honestly this story that Poirot tells us of how evil that man was, so much that the only thing to do was to kill him, could have looked a bit silly, exagerated, pretentious... but not after what we had read about Hastings. He was worried for his daughter, and lead to believe that she was in love with a scoundrel that once before had caused a girl to commit suicide after he had used her. Hastings comes to believe that she wants to elope with him, and her life could be ruined. Norton "explains" to him how he can't do anything, how he has to accept this failure, how he can't protect his own daughter... and Hastings can't reason any more, he has to protect Judith,in the heat of the moment he decides he must do whatever it takes. Hastings plans to kill him, and of course doesn't say a word about it to Poirot, but he could never fool Poirot before, he can't fool him now either. Poirot understands everything and puts a sleeping drug in his hot chocolate, that he himself insists until Hastings drinks it. The next day, having cooled down by a night's sleep, he's already abandoned such a terrible idea, and in the end he'll even learn that Judith never intended to run away with him, it was someone else she was in love with!!  This was huge because Hastings had always been depicted as the gentleman, the honourable man! If he could be brought by that man to the point of orchestrate a murder, that this was really serious!
Poirot's health is very bad, he knows his heart could give out at any given time, and so he himself kills Norton, making everyone else think it was a suicide, of course. Still, he will confess everything in a letter to Hastings; he explains what Norton did, and tries to explain his position, about the fact that nobody should take the law into their own hands but on the other hand Poirot is the law, in a way, and in emergency crisis martial law is adopted... but still confesses he doesn't know if what he did is justifiable or not. He saved Norton's future victims, yes, but Poirot had always disapproved murder... adding at the end that he should go see Elizabeth, the sad girl whose sister had killed their tyrant father, and explain to her everything. Poirot had always been a romantic, and here too I guess he foresaw a way for both his friend Hasting and also for Elizabeth to find companionship in each other.

ITA sipario, l'ultima avventura di Poirot