During the first three decades of the Third Republic there appeared a group of left-wing republicans who became known as Radical-Socialists. As a group they had many ideas in common and tended to vote on many issues with a rather high degree of unity. However, a careful study of their voting record allows three divisions to be made among them. On the extreme Left were the hard core Radical-Socialists (HCRS). They are so designated because their voting record attained a total of about 90% on bills and orders of the day of an advanced social nature. Somewhat less consistent were the Radical-Socialists (RS) who attained at least 75%. Among the former were deputies whose stand for reform was about as consistent as that of the average Socialist. Some of the most famous were Georges Clemenceau, Camille Pelletan, Georges Perin, Tony Révillon, Désiré Barodet, Henri and Félix Mathé, Armand Duportal, Félix Cantagrel, Camille Raspati, Sigismond Lacroix, Ernest Lefèvre, Martin Nadaud, Stéphan Pichon, Emile Chautemps and Marius Chavanne. Among the Radical-Socialists were Antoine Achard, Jules Baulard, Henri Maret, Germain Casse, René Goblet, Paul Doumer, Edouard Lockroy, Gustave Mesureur, Louis-Bernard Montaut, Michel Salis, Emile Brousse, Jules Lasbaysses, Roque de Fillol, Gustave Hubbard, and Benjamin Raspati. Another group, somewhat peripheral to the present study but included in order to round it out, were the social Radicals(SR), or Radicaux de Gauche, as they called themselves after 1881. Their voting record averaged about 60%. The term “left-wing Radicals” includes all the above categories. The moderate or orthodox Radicals were really advanced liberals as regards social legislation, and do not form part of the groups examined in this essay.