This book was ridiculous. I generally like Agatha Christie. I have a soft spot for English Cozy mysteries. This book, though, although it features Hercule Poirot as the detective, is definitely not a cozy. Instead of focusing on a collection of people trapped together in a country house where a murder has taken place, The Big Four is about a painfully implausible international conspiracy. I'm not really a conspiracy theory lover anyway, but even if I was I think I'd find this book deeply silly. My wife and I listened to an audio version while we were on a road trip, and we had a good time laughing at the absurdities together, but I wouldn't recommend it unless you're in the mood to laugh too.