Here’s a quick cast and character guide for CBS’ sci-fi thriller Person Of Interest. Person Of Interest creator Jonathan Nolan started his career as a writer on projects directed by brother Christopher Nolan. Jonathan wrote the short story that served as the basis for 2000’s twisty thriller Memento, and he later worked on the screenplays for Interstellar and the final two entries in The Dark Knight trilogy.

Jonathan Nolan is also behind the TV reboot of Westworld, which is based on Michael Crichton’s cult sci-fi movie of the same name. The show centers on a futuristic theme park where guests interact with incredibly lifelike androids, but after years of abuse and psychological torment, the machines are starting to gain sentience. The first season was acclaimed for its stellar performances and rich themes, though the response to season 2 was more mixed. Nolan’s Person Of Interest began in 2011 and revolves an A.I. dubbed “The Machine” that can predict crimes and the team responsible for investigating its predictions.

Person Of Interest ran for five seasons and while it received good reviews for its early years, it’s considered to have gotten even better with later seasons. Here’s a quick cast and character guide.

Jim Caviezel - John Reese

Jim Caviezel (The Passion Of The Christ) plays protagonist John Reese, an ex-CIA operative who faked his death and is in hiding when Finch recruits him to deal with the information handed out by The Machine. Reese is haunted by the death of a loved one, though he keeps his emotions in check and is a highly skilled combat operative.

Michael Emerson - Harold Finch

Michael Emerson (Saw) is the quirky, withdrawn creator of The Machine. Like Reese, he also keeps his emotions at bay and his past is mysterious, but it’s clear from his willingness to investigate the information given by The Machine he has a conscience too. Finch is a loner by nature though he grows closer to his team as the show progresses.

Amy Acker - Root

Root was originally a guest character on Person Of Interest who was later promoted to the main cast. Root is a hacker who becomes something of a human face for The Machine, and towards the end of the show, its voice. She’s highly skilled in combat, as proven on many occasions. Root also develops a romantic interest in Shaw.

Sarah Shahi - Shaw

Shaw (Sarah Shahi, Bullet To The Head) joined the team in season 2 and is a former assassin who has difficulty expressing emotions. Like Reese, she’s a “primary” asset for The Machine and her relationship with Root forms an important emotional core for the show. Person Of Interest also ends with the suggestion she will continue working with The Machine.

Taraji P. Henson - Detective Carter

Carter, played by Empire’s Taraji P. Henson, was a main character during Person Of Interest’s first three seasons. She initially chases after Reese but later becomes an ally of Finch and Reese, and becomes close friends with the latter.

Kevin Chapman - Detective Fusco

Fusco is a corrupt cop on Person Of Interest who is forced to help Reese and his investigations. Fusco eventually evolves into an important ally throughout the rest of the series.

Next: Person Of Interest: Root’s Shock Death Explained