The progress of the work, increasing as it went on, was so largely helped by the cordial and ample co-operation of the many friends who have so generously assisted them, that they have, indeed, felt their courage amount with occasion. So much material has accumulated on their hands, that a point has been reached whereat it is necessary to make what was originally proposed to form two voIumes into three it is hoped and believed that the importance of the subject will excuse this enforced variation from the original proposal., The work, indeed, has grown in interest as well as in importance as it has progressed, and with the alternative before them, either of abridging the articles under the late letters of the alphabet, thus disregarding the relative proportions of the plan of the work, or of issuing another volume, the decision arrived at cannot fail to be approved by all who desire to see such a prolonged, laborious, and useful enterprise as the compilation of a Bibliography of Printing carried out in its integrity. Accordingly, the present volume brings up the matter to the end of The remaining letters will run into a Third Volume, which may be had by all subscribers to the first two volumes at a proportionate rate of subscription. The range of subjects included has not been modificd, in the way of either expansion or contraction....