I can't believe I had to read through the first 8 pages of reviews before I saw a reference to the novel! I read Dennis Lehane's book several years ago and was so looking forward to the movie, but, was afraid I would be disappointed as I usually am when I see a movie based on a book that was as fantastic as Shutter Island. That was not the case with this movie. It was INCREDIBLE! I had forgotten many details about the book and was completely captivated by the way it was presented in the movie as were all of the other audience members as there was barely a sound or movement throughout the entire 2 + hours. Great movie...I'll probably see it again and I rarely go to the movies!