The Ninth Configuration is an intelligently written  and brilliantly performed delve into belief and madness, good and evil, with  William Peter Blatty delivering a cinematic feast for the mind and soul.
                                Bleeding souls make bitter minds. It is natural for those  who have experienced extreme circumstances of hardship and horror to view the  world as a cesspool void of goodness and grace. War veterans are of particular  note, with many things they have seen (and perhaps even done) in the service of  their country leaving everlasting impacts in the form of PTSD and other  conditions. 
                                It is of little wonder that William Peter Blatty’s  philosophical, theological, and engrossing albeit bizarre The Ninth  Configuration is based in a military home for “disturbed” servicemen. The  home in question is a huge castle, gothic and imposing, the kind of place that  could be used for vampire movies or medieval time period films. When one  patient says, “welcome to Transylvania”, he wasn’t kidding.
                                Into this foreboding palace arrives Colonel Vincent Kane  (Stacy Keach), a psychiatrist tasked with taking control of this group of  whacked out loonies, and determine whether they are actually insane, or faking  it to stay out of service. Kane institutes an unorthodox method to achieve  this: he lets the nuts take over the nuthouse, resulting in all matter of  whacked out spectacle. 
                                The core of The Ninth Configuration is found between  the at times antagonistic conversations between Kane and Captain Billy Cutshaw  (Scott Wilson), and this is where things truly get interesting. Blatty’s  crowning achievement will forever be The Exorcist, and he considers The Ninth Configuration to be its spiritual sequel, linked by Cutshaw,  an astronaut who appears briefly in The Exorcist as a guest at  Chris MacNeil’s (Ellen Burstyn) home, where he receives a chilling warning of  doom by demonically possessed girl Regan McNeil (Linda Blair). It was enough to  drive Cutshaw into despair and insanity, leading to an aborted mission. 
                                Blatty stages the argumentative nature between Kane –  cold, introverted, perhaps masking a madness of his own – and Cutshaw – fiery, calculated,  ready to explode at any time – as that between a belief in God and a belief in,  well, nothingness. Kane’s belief that the world is a good place inhabited by  good people is countered by Cutshaw’s belief (and indeed fear) that we are all  just hovering in an empty universe without purpose. 
                                Blatty presents these ideas with vigorous intelligent  writing, filled with depth, and delivered with spirit by an impressive cast of  character actors, among them Ed Flanders, Joe Spinell, Robert Loggia, and Jason  Miller. Zany, pitch black humour melds seamlessly with drop-dead serious  subjects and moments of shocking violence. A didn’t-see-it-coming twist, that  was ground-breaking at the time, set the tone for many psychological thrillers  to follow.
                                For Blatty, The Ninth Configuration sits in the middle  of a trilogy bookended by The Exorcist and Legion (otherwise known as The Exorcist III). Fueled by his Catholicism,  these films delve into the darkness that plagues humanity, whether it be  violence, corruption, or in the case of The Ninth Configuration, the  supposed absence of God, resulting in a world alone and afloat in a sea of  nothingness. Yet combating this is always the presence of the divine, which  Blatty presents in the sacrificial acts of good men. Part thriller, part  scatterbrain comedy, and part theology lesson, The Ninth Configuration is a film wholly unique and worth seeking.