Just found out William Peter Blatty died. Besides being famous for writing
The Exorcist and directing
The Exorcist III: Legion with an almost arthouse flare for the odd, Blatty wrote the play
Twinkle, Twinkle Killer Kane, which was made into the film,
The Ninth Configuration starring Stacy Keach. The film is quite influential whether or not it is officially acknowledged. Martin Scorsese's
Shutter Island I think in terms of concept shares some similarities thematically. Check it out.