Shutter Island is fairly unique and contains many twist and turns through out the story. You totally believe everything Teddy is going through, then start doubting the same things he does, and eventually question him. There is so much going on and you can come up with many theories on your own and that is all part of the fun. The 4th day part is well done and explained very well, so the reader can follow along. The reason why this book got a 4 star and not a 5 star is simply because of the last few pages. I understand what Lehane was going for, but I felt it was rushed and not set up properly to have much of an affect. I don't expect him to explain what happened, that's an open ended and left to the readers imagination, but the set up and the last few lines made it feel corny and left me thinking, well of course it would end that way. Even with the disappointing ending this book was well written and though out, and overall was a good read.