The plot seams like a strange one: "Set in a future world where America has lost the war on drugs, undercover cop Fred (Keanu Reeves) is one of many agents hooked on the popular drug Substance D, which causes its users to develop split personalities. Fred, for instance, is also Bob, a notorious drug dealer. Along with his superior officers, Fred sets up an elaborate scheme to catch Bob and tear down his operation".
I have been meaning to get round to reading some P.K.D, but I think I have enough on the go at the moment, Dan Brown:The Da vinci Code, Donna Tartt:The Secret History, Mark Haddon:The Curious Incident of The Dog in The Night Time and Iain M. Banks:The Algebraist.