CSI is simply the best US police procedural drama (which, given how many there are, is saying quite a lot). The stories are strong and there is a cast of interesting characters. For me, the central character, Gil Grissom (brilliantly played by William Peterson) is the reason it works so well. Grissom is wonderful character - an introverted and rather unemotional man, a serious scientist who happens to be a criminologist. As such he is free for most of the traditional TV cop baggage, giving the whole series a fresh and interesting perspective. In this series, the CSI team gets on with investigating crime scenes and solving mysteries attempting, but not always succeeding, to do this without bias or preconceptions. They leave the police work to others. The rest of the cast is also very, very good bringing complex and interesting characters to life. Danny Boyle directs most of the episodes with great style, even his habit of focussing in at a microscopic level (e.g. looking at blood vessels etc) works well. Setting the series in Las Vegas works well - the city, the desert, the mountains - they all provide great backdrops and look fantastic. This is the season where CSI really got going, it is even better than the very good season 1. The characters are more fully realised (we start to get glimpses of their life outside work) and there is a very interesting group dynamic. Combined with the excellent story lines and some interesting forensic science this makes for an excellent season of an excellent series.