Undoubtedly one of the most exciting and inspired horror movies ever made. The story is a classic sampling of expressionist paranoia about a hypnotist who uses a somnambulist to do his murders, full of the gloom and fear that prevailed in Germany as it emerged from WWI. There are plenty of extremely boring sociological/critical accounts of the film; best to avoid them and enjoy the film's extraordinary use of painted light and Veidt's marvellous performance. Incidentally, the influence of Caligari on the cinema is much more problematic than some historians suppose. Thematically it has rarely been copied, and the style only really infiltrated in dream sequences and other odd devices.