"Marx did not reject the idea of a human nature. He was right not to do so." That is the conclusion of this passionate and polemical new work by Norman Geras. In it, he places the sixth of Marx's Theses on Feuerbach under rigorous scrutiny. He argues that this ambiguous statement--widely cited as evidence that Marx broke with all conceptions of human nature in 1845--must be read in the context of Marx's work as a whole. His later writings are informed by an idea of a specifically human nature that fulfills both explanatory and normative functions. The belief that Marx's historical materialism entailed a denial of the conception of human nature is, Geras writes, "an old fixation, which the Althusserian influence in this matter has fed upon ... Because this fixation still exists and is misguided, it is still necessary to challenge it." One hundred years after Marx's death, this timely essay--combining the strengths of analytical philosophy and classical Marxism--rediscovers a central part of his heritage.