A poster featuring main characters of the book

From left to right:

Vince Masuka - a lead forensics at the Miami Metro Police. Works with Dexter in the laboratory and in crime scenes. He is the closest person that can be called Dexter's friend.

Maria LaGuerta - a Lieutenant of the Miami Metro Police. A determined woman, head of the Homicide division. Has feelings to Dexter that often confuses him. Has a bad relationship with Dexter's sister Deborah.

Harry Morgan - Dexter's adoptive father. Was a highly-respected detective. Trained Dexter to direct his violence at criminals not to harm innocent people. Had a relationship with Laura Moser, Dexter's biological mother and police informant. Commited a suicide after he realised what a violent and professional killer he had created.

Angel Batista - a detective of Homicide Division. An honest man with a sense of justice.

James Doakes - a sergeant of Miami Metro Police. He is the only person who can see darkness in Dexter. He thinks that Dexter tries to seem ideal to everyone and suspects that he has a secret life.

Rita Bennett (sitting) - Dexter's girlfriend. Doesn't know anything about his secret "activities". Was introduced to Dexter by his sister Deborah.

Deborah Morgan - Dexter's younger foster sister, daughter of Harry Morgan. Doesn't know anything about her father's secret concerning Dexter. Became a police officer inspired by her father and always wanted to be a good detective like he was.

Dexter Morgan - the main character and the narrator. He is a forensics expert and blood spatter analyst of the Miami Metro Police, but has a secret life of a serial killer. Has a kind of alternate personality that he calls "the Dark Passenger", who makes him kill. A biological son of Laura Moser, who was violently killed when he was a boy. This psychological trauma made him a violent serial killer.

The picture features the main characters of the book. They are standing in front of Dexter's boat, that he often uses in his killings. The arm that protrudes from the boat symbolizes the secret that he is hiding from everyone around him.