Thus, with the exception of the fragile memory which the author of this book here consecrates to it, there remains to-day nothing whatever of the mysterious word engraved within the gloomy tower of Notre-Dame, —nothing of the destiny which it so sadly summed up. The man who wrote that word upon the wall disappeared from the midst of the generations of man many centuries ago; the word, in its turn, has been effaced from the wall of the church; the church will, perhaps, itself soon disappear from the face of the earth. It is upon this word that this book.