Martin Ramirez Sostre (March 20, 1923 – August 12, 2015) was an American activist known for his role in the prisoners' rights movement.

[6]Sostre and his coworker, Geraldine Robinson, were arrested at his bookstore on July 14, 1967, for "narcotics, riot, arson, and assault", charges later proven to be fabricated as part of a COINTELPRO program.

According to Sostre, these decisions constituted "a resounding defeat for the establishment who will now find it exceedingly difficult to torture with impunity the thousands of captive black (and white) political prisoners illegally held in their concentration camps.

He was responsible for de-legitimatizing censorship of inmates' mail, invasive bodily exams, and penal solitary confinement.

[13] Black anarchist writer and activist Lorenzo Kom'boa Ervin attributes his initial interest in anarchism to Sostre.

[19] The installation consisted of three bookshelves painted by the artists and placed in the lobby of the Merriweather Library, which was built on the same location one of Sostre's bookstores used to stand.