The German legal philosopher, Otto von Gierke worked to develop a comprehensive history and theory of "social law" (Soziales Recht).
Key tenets of Gierke's work were adopted and brought into English jurisprudence by Frederick W. Maitland.
In France, Léon Duguit developed the concept of social law in his 1911 book, Le droit social, le droit individuel et la transformation de l’état.
A common thread has been an attachment to social justice in a democratic society.
[3] This became central to the thinking of American legal realists during the Lochner era of the early 20th century.