Among his other contributions to the wonderful world of librarianship, Charles Ammi Cutter devised a way to assign an alpha-numeric code for authors' last names. Use of this system allows all books within a particlar Dewey Decimal number to be arranged alphabetically on the shelf, usually by title.
Catalogers try to assign distinct numbers for each name.
So in this case, David Doyle might get assigned a Cutter of D773, and George Doyle D774. It's a bit pesky, and the tables continue to be revised periodically. And names beginning with Sc-something get three letters and the usual bunch of numbers. Cutter Numbers Quiz Click on the button next to the correct answer to receive feedback.