Montesquieu's Considerations on the Causes of the Greatness of the Romans and Their Decline was published almost midway between his Persian Letters (1721) and The Spirit of the Laws (1748). Today it is the least well known of the three, though not through any fault of its own. It may have been the first (and certainly was one of the first) of all efforts to comprehend the whole span of Roman history, and among such efforts it still has few if any peers -- even after a century and a half of the scientific historiography Montesquieu's own writings did so much to engender, and which has now grown disdainful of its philosophic forbears. It was probably one of the works Gibbon had in mind in his Memoirs when he wrote: " ... but my delight was in the frequent perusal of Montesquieu, whose energy of style, and boldness of hypothesis, were powerful to awaken and stimulate the genius of the age." But the context in which it must be understood, and from which it derives its chief value, is not that of history but of political philosophy. In the annals of this subject, it is one of the few instances when a philosopher has undertaken an extended analysis of any particular society, let alone of its entire history. The only comparable thing on Rome is Machiavelli's Discourses, to which it bears a deep inner kinship. But it is simpler than the Discourses, both in structure and meaning. For the most part it uses an historical framework, beginning with Rome's origins and ending with its collapse, and its teaching is in some ways less devious. - Introduction.