In her updated essay "A Cyborg Manifesto: Science, Technology, and Socialist-Feminism in the Late Twentieth Century", in her book "Simians, Cyborgs and Women: The Reinvention of Nature" (1991), Haraway uses the cyborg metaphor to explain how fundamental contradictions in feminist theory and identity should be conjoined, rather than resolved, similar to the fusion of machine and organism in cyborgs. The manifesto is also an important feminist critique of capitalism by revealing how men have exploited women's reproduction labor, providing a barrier for women to reach full equality in the labor market.