The inclusion of the 1967 work Slave Ship alongside the recent The Motion of History (1976) and S-I (1976) in [The Motion of History and Other Plays] reveals Baraka's movement from the view of what he terms "the petty bourgeois of the oppressed nationality," represented by Slave Ship, to a Marxist orientation, represented by The Motion of History and S-I.

After ten years Slave Ship remains a powerful document of mid-1960s Afro-American consciousness. White slavers cannot destroy the African spirit, and indeed unwittingly introduce black culture, especially music, into America via their slave ships….

In short scenes interpreting American historical events ranging from the present to the seventeenth century, The Motion of History portrays black and white proletariats learning to unite against their oppressors. Baraka dispenses with black nationalist preoccupations and focuses on the dramatization of the historical roots of unjust American class and black-white relations. Particularly effective are satirical portraits of solipsistic young bohemians, side-tracked by drugs, Eastern religion and other fashionable diversions, and of poor Southern white types, betrayed and played off against the blacks by establishment whites. Although the idea that black and white workers should unite against their common oppressors is of course not new, Baraka's empathetic presentation of the budding insight and growth of common understanding of individual white and black workers is strong and moving.

S-I presents near-future American political history when the outbreak of war serves as an excuse for fascist repression…. In a recent interview Baraka criticized some of his early work "for celebrating the subjective and the idealistic."… S-I reveals a rather extreme and simplistic idealization of Marxist-Leninism.