Thomas Edward Silverstein (born Thomas Edward Conway; February 4, 1952 – May 11, 2019) was an American criminal who spent the last 42 years of his life in prison after being convicted of three separate murders, with a fourth murder conviction being overturned and Silverstein being implicated in a fifth, while imprisoned for armed robbery. Silverstein spent the last 36 years of his life in solitary confinement for killing corrections officer Merle Clutts at the Marion Penitentiary in Illinois. Prison authorities described him as a brutal killer and a former leader of the Aryan Brotherhood prison gang. Silverstein maintained that the dehumanizing conditions inside the prison system contributed to the three murders he committed. He was the longest-held prisoner in solitary confinement within the Bureau of Prisons at the time of his death. Correctional officers refused to talk to Silverstein out of respect for Clutts.

Silverstein was born in Long Beach, California, to Virginia Conway. Conway had divorced her first husband in 1952 while pregnant with Silverstein and married Thomas Conway, whom Silverstein claimed was his biological father. Four years later, Virginia divorced Conway and married Sid Silverstein, who legally adopted her son.

Silverstein was timid, awkward, shy, and frequently bullied as a child in the middle-class neighborhood where the family lived, in part because his peers mistakenly believed he was Jewish. Virginia Silverstein demanded that her son fight back, telling the boy that if he ever came home again crying because he had been beaten up by a bully, she would be waiting to give him another beating. Silverstein states, "That's how my mom was. She stood her mud. If someone came at you with a bat, you got your bat and you both went at it." At age fourteen, Silverstein was sentenced to a California Youth Authority reformatory where, he said, his attitudes about violence were reinforced. "Anyone not willing to fight was abused."

In 1971, at age nineteen, Silverstein was sent to San Quentin Prison in California for armed robbery. Four years later, he was paroled, but he was arrested soon after along with his father, Thomas Conway, and his cousin, Gerald Hoff, for three armed robberies. Their take was less than $11,000 (equivalent to $85,000 in 2024). In 1977, Silverstein was sentenced to fifteen years for armed robbery, to be served at United States Penitentiary in Leavenworth, Kansas.

While at Leavenworth, Silverstein developed ties with the Aryan Brotherhood. In 1980, Silverstein was convicted of the murder of inmate Danny Atwell, who reportedly refused to serve as a mule for heroin being moved through the prison. He was sentenced to life and transferred to the United States Penitentiary in Marion, Illinois (USP Marion), which was then a high-security facility. The conviction was overturned in 1985 after it emerged that the jailhouse informants who had testified at his trial had perjured themselves on the stand.

At Marion, Silverstein was housed in the "Control Unit", a virtual solitary confinement regime reserved for extreme "management problems" (prisoners prone to assaultive and disruptive behavior) in the prison. He spent his time in solitary confinement with a constant ceiling light, ensuring uninterrupted camera surveillance. He was allowed only two phone calls per month and received his meals through a slot.

In 1981, Silverstein was accused of the murder of Robert Chappelle, a member of the D.C. Blacks prison gang who was serving a life sentence for the 1964 murder of Connecticut police officer Henry Jennings. Silverstein and fellow Aryan Brotherhood member Clayton Fountain were convicted and Silverstein received an additional life sentence. He maintained his innocence. While Silverstein was on trial for Chappelle's murder, the Bureau of Prisons transferred Raymond Lee "Cadillac" Smith, the national leader of the D.C. Blacks prison gang, from another prison into the control unit in Marion. From the moment Smith arrived in the control unit, prison logs show that he began trying to kill Silverstein.

"I tried to tell Cadillac that I didn't kill Chappelle, but he didn't believe me and he bragged that he was going to kill me", Silverstein recalled. "Everyone knew what was going on and no one did anything to keep us apart. The guards wanted one of us to kill the other."