Ar. Holbrook was a person arrested for sedition before the Great War.
An employee at Cambridge Savings and Loan, Holbrook attempted to unionize their workplace. Two pamphlets, "Your Rights at Work" and "You-Nionize Today!" were recovered from their desk. These pamphlets and the testimony of N. Fredricks, the president of Cambridge S&L, were collected by the Cambridge Police Department and transferred to federal officer J. Dobson.
Holbrook is mentioned only in Fallout 4.