In seeking material to illustrate Mrs. Stowe's interesting sketches, two purposes have been kept in view: first, the securing of a series of pictures which, by a judicious selection among different schools and epochs of art, might give a more original and less conventional presentation of the characters than could be had were all the illustrations conceived by the same mind, or executed by the same hand; and, secondly, the choice of such pictorial subjects as were well adapted to reproduction in colors, so as to represent as perfectly as possible, by the rapidly maturing art of chromo-lithography, the real ideas of the painters. The guiding principles of selection have been _aptness of design_ and a rich _variety of effect_. It will be seen that, in pursuit of this purpose, some pictures of world-wide renown have been here reproduced in whole or in part,--the desirable being always limited by the practicable; examples of these are the beautiful "Magdalen" of BATONI, and the main portion of that most wonderful of all pictures, the "Sistine Madonna" of RAPHAEL. The only possible excuse for mutilating this glorious design is the desire to give some slight idea of its color-effect to thousands who have known it only through engravings, and who could never know it otherwise, unless in some such way as this. Among our illustrations are copies of celebrated paintings of more modern date, by the great painters of France, Germany, and England;--such as PAUL DELAROCHE'S graceful scene on the Nile, where Miriam watches little Moses, exposed in the bullrushes; HORACE VERNET'S terrible "Judith"; BAADER'S remorseless "Delilah"; and GOODALL'S lovely picture of "Mary, the Mother of Our Lord," with her offering of two doves in the Temple. Of still another class are those which have been adapted, because of their appositeness, to illustrate subjects which they were not originally painted for: of these, LANDELLE'S "Fellah Woman," well shows the Oriental style and youthful sweetness of "Rebekah" at the fountain, and the "Dancing-Girl" of VERNET-LECOMTE may fairly represent the costume and beauty of Salome, the "Daughter of Herodias." In addition to these varieties, the sixteen plates include several which were designed and painted expressly for this work. One of the most pleasing is "Ruth," by DEVEDEUX of Paris. It is accounted also a peculiar advantage that the "Queen Esther" and the "Martha and Mary"--two very striking and effective pictures--are from the studio of BOULANGER, who shares with Gérome the highest eminence as a delineator of the peculiar and beautiful features of the Orient.