The Murder of Roger Ackroyd: A Hercule Poirot Mystery

I did it! I guessed who the murderer was!
I was a little disappointed as I had the idea planted during the foreword and introduction in my copy. I thought about how it would be an interesting twist if it was the narrator being the murderer, then when he never actually said he closed the window? Curtains. No pun intended.
The twists along the way were still fun, and good ol' poirot is always a lovely time. Just wish I hadn't read the introduction/foreword and could see if I would have figured it out otherwise