Engels on Hegel

Schelling on Hegel
Hegel's Legacy
Review of Marx's Critique of Political Economy

Anti-Dühring, 1878

Free Creations of Thought?
Negation of the Negation
Quantity & Quality
Freedom & Necessity
Dialectics

Socialism: Utopian & Scientific, 1880

Ludwig Feuerbach & the End of Classical German Philosophy, 1886