Moses Hess (21 January 1812 – 6 April 1875) was a German-Jewish philosopher, a pioneer of socialism, and a forerunner of the political movement that became known as Zionism. His intellectual journey included significant contributions to the early development of socialist theory, and he was a close collaborator and an important influence on Karl Marx and Friedrich Engels. In his later life, Hess's focus shifted towards Jewish nationalism, culminating in his seminal 1862 work, Rome and Jerusalem.

Born in the French-occupied Rhineland, Hess was raised in a traditional Jewish home but broke away in his youth to pursue a path of philosophy and radical politics. His first book, The Holy History of Mankind (1837), proposed a socialist society founded on a synthesis of Jewish and Christian ethics, mediated through the philosophy of Baruch Spinoza. In the 1840s, he became a central figure among the Young Hegelians, where he developed a theory of "ethical socialism" and was one of the first thinkers in the German tradition to articulate a sophisticated theory of alienation rooted in social and economic conditions.

After the failure of the Revolutions of 1848, Hess grew disillusioned with the prospects of Jewish integration in Europe. Witnessing the rise of German nationalism and modern antisemitism, he concluded that the Jewish people were a distinct nation, not merely a religious community, and that their existential problems could only be solved through a national revival in their ancestral homeland. Rome and Jerusalem advocated for the establishment of a socialist commonwealth in Palestine, making him a foundational figure of Labor Zionism.

Hess died in Paris in 1875 and was buried in the Jewish cemetery in Deutz, Cologne. In 1961, his remains were transferred to Israel and reinterred in the Kinneret Cemetery. His work represents a unique synthesis of the national and social questions of the 19th century, and he remains a significant, though often overlooked, figure in the histories of both socialism and Zionism.

Moses Hess was born on 21 January 1812 in Bonn, which was then under French rule, into a family whose ancestors may have come from Poland. The Rhineland had been transformed by the French Revolution, which introduced legal equality, abolished feudal privileges, and fully emancipated the Jewish population. This new era of freedom was short-lived; after Napoleon's defeat in 1814, the region was granted to the Kingdom of Prussia, which rescinded the rights Jews had acquired under the French. This reversal created a profound sense of trauma and dislocation among Rhenish Jews, who, after tasting freedom, were pushed back into a state of civic inequality. While some, like Heinrich Heine and Karl Marx's father, converted to Christianity to regain their status, Hess's family reacted by becoming more fiercely attached to their traditional religion. This experience shaped a generation of radical Jewish thinkers from the region.

Hess came from a family with rabbinical ancestors on both sides. His father, a businessman, moved the family to the more commercially vibrant city of Cologne in 1816 to set up a sugar refinery, but left the five-year-old Moses in Bonn to be raised by his devoutly religious maternal grandfather. Cologne's Jewish community was small and lacked educational infrastructure, so Hess remained in Bonn to receive a traditional Jewish religious education in the Bible and Talmud under the guidance of his grandfather, whom Hess later recalled as an "extremely orthodox" and learned man. In a diary entry from 1836, however, Hess recalled his formal teachers with anguish, calling them "inhuman beings" (Unmenschen).

In the Jewish Quarter [Judengasse] was I born and educated; until my fifteenth year, they tried to beat the Talmud into me. My teachers were inhuman beings [Unmenschen], my colleagues were bad company, inducing me to secret sins; my body was frail, my spirit raw.

After his mother's death in 1826, Hess joined his father in Cologne and was expected to enter the family business. The move to a larger, more cosmopolitan city made him painfully aware of his limited, ghetto-based education. He rebelled against both his father's commercial world and the prospect of a rabbinic career, choosing instead to pursue a life of letters. He quarreled with his father and, in 1833, left home with a small sum of money, travelling to Holland and France, where he experienced poverty and first encountered socialist ideas. Lacking a formal secular education, he embarked on an intensive program of self-study, reading voraciously in German philosophy—including Immanuel Kant, Friedrich Wilhelm Joseph Schelling, and Georg Wilhelm Friedrich Hegel—and French thinkers like Jean-Jacques Rousseau. He was particularly impressed by Baruch Spinoza, whom he saw as a model for a modern version of the Hebraic prophetic tradition. The only other Jewish works he mentioned from this period were Moses Mendelssohn's Jerusalem and Spinoza's Tractatus.