Looking at the state of research on Karl Marx's work, it is immediately apparent that very little attention has been paid to law in particular. This is all the more remarkable given that Marx first came into contact with the socio-political problems of his time as a student of law and only later became closely intertwined with the philosophy of Hegel. Contrary to the mostly systematic considerations of law in Marx's work to date, this work chooses a different approach by reconstructing his legal thinking starting from its roots, Hegel's philosophy of law and its further development by Eduard Gans, and presenting it in its ongoing development. The method of developmental history is not limited to the main writings of the oeuvre, but also includes the peripheral parts of the work. This is the first comprehensive reconstruction of the history of the development of legal thought, which not only succeeds in documenting the constant relevance of law in Marx's thinking, but also his adherence to Hegel's philosophy of law, including its specific connection between law and freedom.