For anyone who struggled with trying to make sense of this Dennis Lehane mystery, here is a graphic novel's interpretation that might help shed some light. 

 

Christian de Metter is another one of those award-winning European illustrators who had this book honored in France. 

 

There has been a lot of debate about the ending of Shutter Island.  It is said that one picture is worth a thousand words.  There are a great many pictures in this graphic novel.  Words still escape me.