Assigned by the United States Library of Congress, an LCCN is a reference number used to locate the bibliographic data of a book published in the United States. Unlike an ISBN, your LCCN does not refer to a specific edition or format, and can be used for hardcover, paperback, and subsequent editions of the same book.

In a word: yes. One of the most important reasons to obtain an LCCN for your book is for discoverability. Not only does the number help the...