Three powerful ideologies emerging in the first half of the nineteenth century combined to destroy the Old Order in Western Europe and shape its future: liberalism, nationalism and socialism. Little is known about the genesis of the three words that served to designate these ideologies. The most casual research will reveal astonishing contradictions among the recognized authorities, the lexicographers, not to speak of some glaring mistakes that appear in the writings of notable historians. For such shortcomings there is no lack of excuse. Indeed, in order to produce a sound and indisputable history of these three master words, it is necessary to sift so much material—no less than the whole printed output of the age—that the task appears quite hopeless. The present essay, therefore, is clearly open to criticism and revision; it has no other purpose than to suggest some guidelines of approach and to patch together some of the scraps of evidence now available. All this, let it be well understood, being confined to the French language and scene. Similar probes in the English or German soil would undoubtedly reveal different patterns.