'A Scanner Darkly'' is an adaptation of the famous novel by Philip K. Dick (''Blade Runner'', ''Minority Report'', ''Total Recall''). Like director Richard Linklater's earlier effort, ''Walking Life', it uses the rotoscoping animation technique, meaning that live-action movements of real actors (Keanu Reeves, Winona Ryder, Robert Downey Jr. and Woody Harrelson among them) are traced on paper, achieving completely realistic results (this technique was invented by animation pioneer Max Fleischer, though he didn't use it in his most famous cartoons starring Betty Boop or Popeye). The story concerns an undercover narcotic officer and his paranoid drug addicted friends. But the undercover cop is really spying on himself - a fact unknown to his superiors because the identities of drug cops are hidden by "scramble suits," psychedelic-looking devices that turn the user into sort of a human quilt. If this was a live-action film, those suits couldn't be credible, but rotoscoping animation is a perfect medium for it. And the reason the film succeeds so well is the humour - dark, absurd, creepy, understated and full of irony. Highly recommended.