Dexter is an American crime drama mystery television series that aired on Showtime from October 1, 2006, to September 22, 2013. Set in Miami, the series centers on Dexter Morgan (Michael C. Hall), a forensic technician specializing in bloodstain pattern analysis for the fictional Miami Metro Police Department, who leads a secret parallel life as a vigilante serial killer, hunting down murderers who have slipped through the cracks of the justice system. The show's first season was derived from the novel Darkly Dreaming Dexter (2004), the first in a series of novels by Jeff Lindsay. It was adapted for television by James Manos Jr., who wrote the first episode. Subsequent seasons evolved independently of Lindsay's works.
In February 2008, reruns (edited down to a TV-14 rating) began to air on CBS in the wake of the shortage of original programming ensuing from the 2007–08 Writers Guild of America strike, thus the reruns on CBS ended after one run of the first season. The series enjoyed mostly positive reviews throughout its run and popularity. The first four seasons have received universal acclaim, although reception dropped drastically as the series progressed. The show has also won many awards, including two Golden Globes won by Hall and John Lithgow for their roles as Dexter Morgan and Arthur Mitchell, respectively. Season four 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 at that time.
In April 2013, Showtime announced that season eight would be the final season of Dexter. The season-eight premiere was the most watched Dexter episode with more than 3 million viewers total for all airings that night. The original broadcast of the series finale—shown at 9 pm on September 22, 2013—drew 2.8 million viewers, the largest overall audience in Showtime's history.
In October 2020, it was announced that Dexter would return with a 10-episode limited series, starring Michael C. Hall in his original role, with Clyde Phillips returning as showrunner. It is slated to premiere in late 2021.