Readers of this journal will be familiar with Lenore Rapkin's name. Lenore has solicited and edited feature articles for inclusion in Canadian Law Libraries for a number of years. In her business life, Lenore specializes in cataloguing at the McGill University Law Library. Recently she has been working on preparing a lexicon to assist both librarians and researchers to assign the most appropriate Library of Congress subject headings to Civil law publications. This lexicon will be published by William S. Hein early in 1998. The following article, written by Professor Nicholas Kasirer, a professor at McGill University Faculty of Law, is a reprint of the introductory essay in the lexicon and appears here by permission. One mandate of Canadian Law Libraries is to share useful insights into the particular knowledge and skills necessary to be effective law librarians. This article is a very clear statement of the value, indeed the necessity, of the "background" work performed by librarians everywhere. I am delighted that Professor Kasirer offered this article for publication in CLL and trust that the introduction to Lenore's lexicon will encourage the unsung cataloguers we all too often take for granted.