Krzysztof Kieślowski's Dekalog is one of the greatest achievements of the late 20th century - as much an intricate work of moral philosophy as it is a collection of psychologically riveting narratives. Each standalone story revolves around the consequences arising from a breach of one of the Ten Commandments, but this is no finger-wagging religious tract: Kieślowski was one of film history's keenest observers of human nature, and his troubled, vainglorious, self-deceiving, deeply flawed characters (many played by some of Poland's finest character actors) are universally recognisable.