When the plan of the Popular Catholic Library was formed, the author of the following little work was consulted upon it. He not only approved of the design, but ventured to suggest, among others, a series of tales illustrative of the condition of the Church in different periods of her past existence. One, for instance, might be called "The Church of the Catacombs;" a second, "The Church of the Basilicas;" each comprising three hundred years; a third would be on "The Church of the Cloister;" and then, perhaps a fourth might be added, called "The Church of the Schools."<br><br>In proposing this sketch, he added - perhaps the reader will find indiscreetly - that he felt half inclined to undertake the first, by way of illustrating the proposed plan. He was taken at his word, and urged strongly to begin the work. After some reflection, he consented; but with an understanding, that it was not to be an occupation, but only the recreation of leisure hours. With this condition, the work was commenced early in this year; and it has been carried on entirely on that principle.<br><br>It has, therefore, been written at all sorts of times and in all sorts of places; early and late, when no duty urged, in scraps and fragments of time, when the body was too fatigued or the mind too worn for heavier occupation; in the road-side inn, in the halt of travel, in strange houses, in every variety of situation and circumstances - sometimes trying ones.