Gramsci’s major theoretical work was written in prison without library access

Evidence

The main body of Gramsci’s theoretical ideas are scattered throughout his occasional essays and polemical writing—he was an active and prolific political journalist—and, of course, in the great collection of Prison Notebooks, which Gramsci wrote without benefit of access to libraries or other reference books, either during his enforced leisure in Mussolini’s prison after his arrest (1926–1933) or after his release, but when he was already terminally ill (1933–1937). — Stuart Hall, Essential Essays, Volume 2, 77