Just a word in regard to the actual amount of material in the book. The statement of the Publishing Board that the third edition contains about three times the material in the second edition has been questioned on the score that the new edition is printed on one side of the leaf only. It should be remembered, however, that only the printed pages are numbered, so that the list of headings in the third edition occupies 397 pages, double column, while the second edition contained but 193 half pages and 12 full pages. That is, the printed matter in the third edition occupies nearly four times the space filled in the second edition. Moreover, the type is smaller, so that the new page contains twelve lines more than the old one. Therefore, allowing for the blank space occasioned by the disparity of the lists of "See also" and "Refer from" references, it is believed that the estimate of three times the material of the second edition is conservative. The subject was continued in a paper by Miss MARY W. MACNAIR, of the Library of Congress on THE LIBRARY OF CONGRESS LIST OF SUBJECT HEADINGS The list of subject headings issued by the Library of Congress is used also, for reference and comparison, by many other libraries throughout the country. It has been suggested that a statement in regard to the purpose, scope, and manner of printing of the list, might be useful to the librarians receiving it, and possibly valuable as well to others who are interested in the undertaking, and who may be, to some extent, unfamiliar with the Library of Congress catalog. The printing of the list of subject headings was begun in the summer of 1909. Up to that time, the second edition of the A. L. A. subject headings had been used as a basis for the subjects assigned in the Library of Congress catalog. But so many additions and alterations had been made in our interleaved copies of the A. L. A. list, that the need of an entirely new list of headings began to be urgently felt, although the difficulty had been partially obviated by the printing of lists of additions to the old A. L. A. list, for distribution to the catalogers at the Library of Congress. At this date the third edition of the A. L. A. list was already in preparation, yet it was considered wiser to print a list of the Library of Congress headings, rather than to co-operate in the A. L. A. undertaking, as the headings needed in our catalog differed to such an extent from those required for the average public library.