ER began as a collaboration between
Steven Spielberg and
Michael Crichton. Their initial goal was to come up with a
movie based on the doctors and events in a
hospital emergency room, to be directed by Spielberg. However, things didn't quite go as planned and the project was dropped. Spielberg directed a movie adaptation of Michael Crichton's
Jurassic Park instead.
Crichton kept at it, though, and his plan for a movie evolved into a plan for a television series, which he came to believe would be a much more fitting way of telling an ongoing, continuous story. Warner Brothers produced the show and NBC picked it up in 1994. The show instantly shot up to number one in the ratings.
Eight years later, ER is still one of the most popular shows on television, consistently ranking first in its timeslot. It also holds the distinction of being one of the most realistic, well-written, well-acted and (perhaps not coincidentally) expensive shows on TV. The cast has gone through many changes since the first episode, but even though only two original cast members remain (with one leaving the show this season) ER is every bit as good as (if not better than) the day it first aired.
It's also no coincidence that the show has boosted the careers of many, many people. George Clooney went from a relative unknown to an international superstar almost overnight, as did (to a lesser extent) Noah Wyle, Ming-Na Wen, and Julianna Margulies. In addition to actors, ER has spawned several other big names. Director Mimi Leder got her start directing episodes of China Beach and, later, ER. Quentin Tarantino even directed an episode, although his career was already well-established.
All in all, this show has some of the highest production values on television, and is probably responsible for the recent bombardment of high quality TV -- something that I don't think anyone's complaining about.