If this book had been intended merely to satisfy a vulgar and commonplace curiosity, it would only have consisted of a few pages. My aim has been a loftier one. I have endeavoured, while concerning myself with the most famous and romantic of State-prisoners, to write the history of the principal individuals in whom people have beheld the Man with the Iron Mask. As regards some of these I have been compelled to lay bare the private life of Louis XIII. and Anne of Austria, and in order to refute the accusations with which the memory of this princess has been sullied, I have not hesitated to touch upon certain delicate points, and to follow her accusers on to the ground on which they have carried the discussion. But I have imposed upon myself the obligation of always respecting my readers, and of influencing their judgment without offending their taste. I have traced the others throughout their adventurous careers and agitated existences, and some of them even through their captivity, spent, sometimes in the monotonous inaction of solitude, sometimes with the resignation of the sage, or animated more frequently still by daring attempts at flight which the incessant vigilance of the most scrupulous of gaolers always foiled. Thus there will be found grouped together in this work Louis XIII. and Anne of Austria, the seductive Buckingham and the affecting Vermandois, the versatile Monmouth and the adventurous Beaufort, Lauzun the rash, and Fouquet, rendered admirable by his resignation and Christian virtues, the unfortunate Matthioly, and Saint-Mars, whose memory, and even existence, is inseparable from that of his prisoners. The sole and firm ground-work of this book are the materials, for the most part unpublished, to be found in our Archives. For the space of two years I have been collecting them in the different depositories of manuscripts; and at the Ministries as at the Archives of the Empire, at the Imperial Library as well as at the Arsenal, at the Institute as at the Hôtel de Ville, I have everywhere met with the most cordial reception, the most unreserved liberality, and the most invaluable courtesy. It is my duty, and at the same time my pleasure, to testify my gratitude to MM. Camille Rousset, Gallet de Kulture, Margry, de Beauchesne, Lacroix, Ravaisson, Sage, Aude, and Read. The treasures of our Archives are not only rendered accessible by the goodwill of their Keepers, but are also made easy of consultation by the order which these gentlemen have introduced among the profusion of documents by means of classifications as clear as they are ingenious.