Dexter is an Emmy and Golden Globe Award-winning American television drama series that airs on the pay-TV channel, Showtime. In February 2008 reruns began to air on CBS. Set in Miami, the series centers on Dexter Morgan (Michael C. Hall), a serial killer who works for the Miami Metro Police Department as a blood-spatter analyst.

The show is based on characters created by Jeff Lindsay for his series of Dexter novels. It was adapted for television by Emmy Award-winning screenwriter James Manos, Jr., who wrote the pilot episode.

On October 21, 2008, Showtime renewed the series for a fourth and fifth season, each consisting of twelve episodes. Season 4 aired its season finale on December 13, 2009 to a record-breaking audience of 2.6 million viewers, making it the most-watched original series episode ever on Showtime.

Source: Wikipedia.org