The Poirot books are all basically stand alone novels and don't require previous knowledge of the character to enjoy them. There is a reader's guide on the Agatha Christie website that tells you this same thing, but also points out which books to read before others. This might be because a later book references an earlier book and would reveal the killer, or it might be a direct reference to something that happens to Poirot that indirectly spoils the previous book.
I'll link the pdf from the Agatha Christie website, but I'll post this first: The last Poirot novel is called "Curtain". That is the final book about Poirot and should be read last. The pdf also has this as the first point that they make, but I figured it was better to be safe than sorry in this case.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.