For more than a century, libraries have had professionals who made it their business to select, acquire, display, and bind academic, professional, and trade journals, and then to assist library customers in their use. Over the last three years (1999-2001), the Journals of the Century Project set out to honor these serials librarians by having a panel of subject expert librarians offer their views of what they each regarded as the most influential journals in their respective fields over the last 100 years. As befitted their considerable acumen, each of the contributing authors was given considerable leeway in his or her approach to this task. The only mandate was that the authors be highly discriminating rather than all-inclusive. Owing to the courtesy of Jim Cole, the editor, these contributions appeared initially in the four issues that made up Volume 39 of The Serials Librarian. We reproduce and review them now in six clusters of individual chapters showing the characteristic pattern each cognate group displayed in terms of the geographic origin of their journals and the sectors of the publishing industry responsible for producing them. An index by title with ISSNs for the print versions of the journals follows.