A lovely jumping point for learning about German Expressionism in the cinema - if not its FIRST example, perhaps, then certainly one of its best known, behind Metropolis. The dreamlike nonsensicality of the plot and the flat cardboard sets, so sharply and strikingly designed that you forget their lack of actual dimension, create a totally bizarre cinematic world, quite unlike anything of its time or any other time. It meanders into territory that occasionally grows repetitive or uninteresting, but the ending is great, casting a shadow of irresolution and doubt that you don't often find in films of the 20s. The whole enterprise is surprisingly eerie, as befitting its position of arguably the first true horror movie, and the shadowy set design and Conrad Veidt's menacing somnambulist seem to slide perfectly into this sanguine world. Even the intertitles, dark and chaotic, are an excellent fit for the movie.
You'll probably see this in a film class, if that's your academic pursuit of choice, but if you have even a remote interest in the history of the genre or film in general, Dr. Caligari is worth a visit.