The Good Nurse: A True Story of Medicine, Madness, and Murder by Charles Graeber tells about the investigation and conviction of Charlie Cullen, a nurse who killed patients. The killings occurred at random in the hospitals where he worked over his sixteen year career. It is a frightening tale that might not have ended in a conviction if one woman had not come forward and helped the police end the killing spree. The Good Nurse is a story of caution about the medical field that will frighten most readers.

Charlie Cullen had a difficult childhood. He was one of eight children. He was born so late in his parents' lives that his father died a short time before his birth. Charlie was close to his mother, but he was often tortured by his older sisters and their boyfriends. Charlie fell into a depression when his mother died after a car accident. He entered the Navy to give his life some purpose. He despised the Navy.

After Charlie's return to civilian life, he enrolled as the only man in nursing school. While working his way through school, he met and fell in love with Adrianne. Charlie and Adrianne married. He began his first job almost immediately. They had a daughter within a year, but Adrianne began to notice that Charlie acted oddly around the baby and their dog. Adrianne began to notice other odd things as the years passed, including abuse of the dogs and Charlie’s heavy drinking, even around the children. Adrianne eventually filed for divorce, claiming Charlie was abusive. Charlie lost custody of his two daughters.

Charlie moved from job to job. He would do well on a job for awhile. Then, odd behavior would cause him to come under scrutiny. Charlie's first job was at St. Barnabas Hospital where he was suspected of spiking IV bags with insulin. Next, Charlie moved on to Warren Hospital. He was eventually let go from that hospital for suspicion of causing the death of a patient. A short time before he had been arrested and charged with breaking into a co-worker’s house.

From Warren, Charlie went to Morristown. While there, Charlie was accused of not caring for his patients properly and leaving their rooms messy. Charlie tried to commit suicide for a second time and ended up spending time at Greystone Psychiatric Hospital again.

Charlie started working at a nursing home called Liberty. At Liberty, Charlie appeared to be involved in the suspicious deaths of two men. After one of the deaths, another nurse was fired. In her lawsuit against Liberty, she named Charlie as the suspect. Charlie left Liberty and got a job at Lehigh Valley Hospital. At Lehigh, Charlie was involved in several deaths, including that of a young burn patient. After another failed suicide attempt, Charlie was let go from Lehigh Valley Hospital. From Lehigh, Charlie moved to Saint Luke’s, where he was eventually accused of throwing away perfectly good medication and stealing others.

Charlie worked at Somerset Medical Center for more than a year. During his time there, he met Amy Loughren. Amy and Charlie became good friends. Amy was unaware that Charlie was killing patients with overdoses of medication, often a cocktail of medicines. Charlie had to be tricky about the way he got the drugs because the hospital used a system called Pyxis to control the drugs being used. Charlie was nearly caught once when the hospital became concerned about the death of Reverend Gall, but the investigation stalled.

A pharmacy employee at Somerset called the Center for Poison Control during the investigation into Gall’s death. The head of the Center for Poison Control warned Somerset that they should involve the police, but they did not. Instead, they informed the Department of Health who failed to act. The police were not brought in on the case until five months later.

Tim Braun and Danny Baldwin were relentless in their investigation of Charlie. However, they did not understand much of the information presented to them because it was medical in nature. However, Amy realized with just a look at Charlie’s Pyxis records that he was doing something wrong. She agreed to help the police. Amy made several calls to Charlie that were recorded. The police eventually got enough information to arrest Charlie; and, he confessed.

Charlie was convicted of thirteen murders in the hospitals where he worked. For three years, he helped police look through medical records to identify other victims. Charlie was sentenced to life in prison. At one point, however, Charlie did something to save a human life. He donated a kidney to the brother of his former girlfriend.