A timed comparison was made of two methods of searching. Five bibliographic searchers timed themselves while searching by possible main entries in the National Union Catalog. The authors then timed themselves searching the same items by title in the English Language Books by Title and in Library of Congress National Program for Acquisitions and Cataloging (LC NPAC) depository card file arranged by title. Comparisons revealed that, for a sample size of 771 items, searching by main entries in the National Union Catalog is 89.3 percent slower than searching by title in the LC NPAC file, and it is 84.8 percent slower than searching by title in the English Language Books by Title. (Author/EH)