Take care of her!
~ Judge Ethan Rickover, immediately before committing suicide.

Ethan Rickover is the primary antagonist of the television series Monk. Though members of his organization make only a handful of appearances and he himself only appears in the finale, he is directly responsible for Adrian Monk's motivation for pursuing detective work.

He was portrayed by Craig T. Nelson, who also portrayed Martin Barrow.


He was a respected college professor who had a penchant for seducing his students, including Trudy Ellison. Trudy was impregnated as a result of their affair, which Rickover was determined to keep a secret. After their daughter, Molly, was born, Rickover manipulated the midwife Wendy Stroud, into telling Trudy that Molly died nine minutes after birth, while putting the child up for adoption.

Fourteen years later, in 1997, Rickover was nominated as federal judge, and when Stroud— who has since "found Jesus" —finds out about this, she informs Rickover that she plans on telling everyone about his affair and illegitimate child. Rickover realizes any information regarding these events could be potentially damaging to his political career and has Stroud killed as damage control, burying her body in his backyard.

For safe measure, Rickover hired Frank Nunn to plant a bomb in Trudy's car. Trudy already suspected that Rickover was involved with Stroud's death and felt especially threatened by an ominous phone call arranging a meeting in a parking garage. As such, Trudy leaves a video message for her husband, Adrian Monk, asserting her suspicions regarding Rickover, in the case that something were to happen to her. After Trudy's murder, Adrian Monk dedicated his life to pursuing his wife's killer, but was unable to find evidence and refused to open Trudy's Christmas gift to him, which contained her last recorded message. However, the crime lord Dale the Whale Biederbeck III pointed Monk towards the bomb-maker, Warrick Tennyson, who described Nunn's six-fingered hands. After Nunn was killed, Rickover was indirectly mentioned in the evidence as being "The Judge".

Twelve years later, in "Monk and the End", Rickover has come far in his career, having been recently nominated for the Calafornia Supreme Court, although he still lives in the same house. At this time, Dr. Malcolm Nash, the doctor at the clinic that Stroud worked at, is going through some old records at the clinic and is able to piece together what happened to Stroud and Rickover's involvement in it. Nash, who was talking to Monk and Stottlemeyer when the call came in about Trudy's death, subsequently makes several calls to Rickover in an attempt to blackmail him with this information, so Rickover hires Joey Kazarinski to kill the doctor.

Monk gets involved in the investigation following Nash's death and is able to uncover evidence at the scene of the crime linking back to Kazarinski. Rickover finds out about this when Captain Stottlemeyer comes over to his house to sign a warrant to search Kazarinki's premises. Fearing that Monk's involvement in the investigation may ultimately lead back to him, Rickover orders Kazarinski to kill Monk as well. Kazarinski poisons Monk's wipes with a deadly synthetic toxin, one that will kill him in a period of two or three days. When Kazarinksi gets hit by a train and dies, Rickover thinks himself to be cleared of any suspicion, but unbeknownst to him, Trudy had made video for Monk to watch in the event of her death explaining her affair with Rickover and their illegitimate child.

Having just found out about the video, Monk confronts Rickover and informs him that he knows he was behind Trudy's death, although he has no other evidence to back this up. Eventually, Monk realizes why Rickover refused to move away from his longtime house and confronts Rickover again in his yard as he is returning home, forcing Rickover at gunpoint to dig up Wendy Stroud's body. The body is eventually found, with both Monk and the police present at the scene, and Rickover confesses to the murders of Wendy Stroud and Trudy Monk. Deciding not to kill Rickover, Monk drops the gun to the ground which Rickover then picks up and holds to his own head, saying "You take care of her!", before pulling the trigger and killing himself. Because he is the only person left to to know that Trudy's child was still alive, no one is able to figure out what exactly he meant by this, until Monk meets the daughter for himself.