A quest for the Golden Age — such was the desperate attempt to take France back to the Belle époque of the turn of the century, embellished by memory, after the nightmare of World War I and the postwar disappointments, under the leadership of the Radical Party. Why was the Radical Party the promoter of an enterprise which answered the more or less clearly articulated wishes of so many Frenchmen, even outside its ranks ? This analysis of the character and functions of the Radical Party in the early years of the 20th century, and of its héritage, is meant as an answer to that question. It describes its militants, its géographie distribution, its audience throughout France, its ideas and programmes. Led by the prestigious and towering Edouard Herriot, the Radicals proposed to their fellow Frenchmen, as an alternative to a disappointing society, the reconstruction of an exalted past.