“I had written this book because it was so difficult to do, and that idea fascinated me. Ten people had to die without it becoming ridiculous or the murderer being obvious. I wrote the book after a tremendous amount of planning, and I was pleased with what I had made of it. It was clear, straightforward, baffling, and yet had a perfectly reasonable explanation; in fact, it had to have an epilogue in order to explain it. It was well received and reviewed, but the person who was really pleased with it was myself, for I knew better than any critic how difficult it had been.”

Agatha Christie, 1939